Menopause
Encyclopedia
Menopause is a term used to describe the permanent cessation of the primary functions of the human ovaries: the ripening and release of ova and the release of hormone
s that cause both the creation of the uterine lining and the subsequent shedding of the uterine lining (a.k.a. the menses or the period). Menopause typically (but not always) occurs in women in midlife, during their late 40s or early 50s, and signals the end of the fertile
phase of a woman's life.
The transition from reproductive to non-reproductive is the result of a major reduction in female hormonal production by the ovaries. This transition is normally not sudden or abrupt, tends to occur over a period of years, and is a natural consequence of aging. However, for some women, the accompanying signs and effects that can occur during the menopause transition years can significantly disrupt their daily activities and sense of well-being. In addition, women who have some sort of functional disorder affecting the reproductive system (e.g., endometriosis
, polycystic ovary syndrome
, cancer of the reproductive organs) can go into menopause at a younger age than the normal timeframe. The functional disorders often significantly speed up the menopausal process and create more significant health problems, both physical and emotional, for the affected woman.
The word "menopause" literally means the "end of monthly cycles" from the Greek
word pausis (cessation) and the root men- (month), because the word "menopause" was created to describe this change in human
females, where the end of fertility is traditionally indicated by the permanent stopping of monthly menstruation
or menses. However, menopause also exists in some other animals, many of which do not have monthly menstruation; in this case, the term mean a natural end to fertility that occurs before the end of the natural lifespan.
The date of menopause in human females is formally medically defined as the time of the last menstrual period (or menstrual flow of any amount, however small), in those women who have not had a hysterectomy
. Women who have their uterus
removed but retain their ovaries do not immediately go into menopause, even though their periods cease. Adult women who have their ovaries removed however, go immediately into surgical menopause, no matter how young they are.
Menopause is an unavoidable change that every woman will experience, assuming she reaches middle age
and beyond. It is helpful if women are able to learn what to expect and what options are available to assist the transition, if that becomes necessary. Menopause has a wide starting range, but can usually be expected in the age range of 42–58. An early menopause can be related to cigarette smoking, higher body mass index, racial and ethnic factors, illnesses, chemotherapy, radiation and the surgical removal of the uterus and/or both ovaries.
Menopause can be officially declared (in an adult woman who is not pregnant, is not lactating, and who has an intact uterus) when there has been amenorrhea (absence of any menstruation) for one complete year. However, there are many signs and effects that lead up to this point, many of which may extend well beyond it too. These include: irregular menses, vasomotor
instability (hot flashes and night sweats), atrophy of genitourinary
tissue, increased stress, breast tenderness, vaginal dryness, forgetfulness, mood changes, and in certain cases osteoporosis
and/or heart disease. These effects are related to the hormonal changes a woman’s body is going through, and they affect each woman to a different extent. The only sign or effect that all women universally have in common is that by the end of the menopause transition every woman will have a complete cessation of menses.
, the most typical age range for menopause (last period from natural causes) is between the ages of 40 and 61 and the average age for last period is 51 years. The average age of natural menopause (in Australia) is 51.7 years, although this varies considerably from one individual to another. In some countries however, such as India
and the Philippines
, the median age of natural menopause is considerably earlier, at 44 years.
s experience menopause significantly earlier than non-smokers. Women who have undergone hysterectomy with ovary conservation go through menopause on average 3.7 years earlier than the expected age.
to age 40, and this is known as premature ovarian failure
(POF). Spontaneous premature ovarian failure affects 1% of women by age 40, and 0.1% of women by age 30. POF is not considered to be due to the normal effects of aging. Some known causes of premature ovarian failure include autoimmune disorders, thyroid
disease, diabetes mellitus
, chemotherapy
, being a carrier of the fragile X syndrome
gene, and radiotherapy. However, in the majority of spontaneous cases of premature ovarian failure, the cause is unknown, i.e. it is generally idiopathic
.
POF is diagnosed or confirmed by high blood levels of follicle stimulating hormone (FSH) and luteinizing hormone
(LH) on at least 3 occasions at least 4 weeks apart. Rates of premature menopause have been found to be significantly higher in fraternal and identical twins
; approximately 5% of twins reach menopause before the age of 40. The reasons for this are not completely understood. Transplants of ovarian tissue between identical twins have been successful in restoring fertility.
Menopause is perhaps most easily understood as the opposite process to menarche
, the start of the monthly periods. However, menopause in women cannot satisfactorily be defined simply as the permanent "stopping of the monthly periods", because in reality what is happening to the uterus
is quite secondary to the process; it is what is happening to the ovaries
that is the crucial factor.
As an illustration of the central role that the ovaries play, it is worth pointing out that when for medical reasons the uterus has to be surgically removed (hysterectomy
) in a younger woman, her periods will of course cease permanently, and the woman will be incapable of pregnancy, but as long as at least one of her ovaries is still functioning, the woman will not have reached menopause. Even without the presence of the uterus, ovulation
and the release of the sequence of reproductive hormones will continue to cycle on, until menopause is reached. In contrast to this, in circumstances where a woman's ovaries are removed (oophorectomy
), even if the uterus were to be left intact, the woman will immediately be in "surgical menopause". Surgical menopause is a menopause which is induced both suddenly and totally, by removal of both ovaries prior to the age of natural menopause.
On average, assuming there has been no surgical intervention, the first evidence of the onset of the menopause transition time is slight variations in the length of the menstrual cycle. These variations become more pronounced over time, and eventually lead to cycles that can be considerably longer or considerably shorter than usual, flow that can be significantly lighter or heavier than usual, skipped ovulations, skipped periods, and spans of time of many months with no flow at all, after which menstruation may resume. The transition is considered to be over once a woman has experienced 12 months without any menstrual bleeding at all, even though perimenopause effects may extend well beyond this point in time. The term "perimenopause", which literally means "around the menopause", refers to the menopause transition years, a span of time both before and after the date of the final episode of flow.
levels.
In younger women, during a normal menstrual cycle
the ovaries produce estradiol
, testosterone
and progesterone
in a cyclical pattern under the control of FSH and luteinising hormone (LH) which are both produced by the pituitary gland
. Blood estradiol
levels remain relatively unchanged, or may increase approaching the menopause, but are usually well preserved until the late perimenopause. This is presumed to be in response to elevated FSH levels. However, the menopause transition is characterized by marked, and often dramatic, variations in FSH and estradiol levels, and because of this, measurements of these hormones are not considered to be reliable guides to a woman's exact menopausal status.
Menopause is based on the natural or surgical cessation of estradiol and progesterone production by the ovaries, which are a part of the body's endocrine system
of hormone
production, in this case the hormones which make reproduction possible and influence sexual behavior. After menopause, estrogen continues to be produced in other tissues, notably the ovaries, but also in bone, blood vessels and even in the brain. However the dramatic fall in circulating estradiol levels at menopause impacts many tissues, from brain to skin.
In contrast to the sudden fall in estradiol during menopause, the levels of total and free testosterone
, as well as dehydroepiandrosterone sulfate (DHEAS) and androstenedione
appear to decline more or less steadily with age. An effect of natural menopause on circulating androgen
levels has not been observed. Thus specific tissue effects of natural menopause cannot be attributed to loss of androgenic hormone production. However, women who have had their ovaries surgically removed, who have had their ovaries damaged by chemotherapy or radiotherapy, or who have ovarian gonadotropin suppression, do have loss of ovarian androgen production as a result.
Menopause can be surgically induced by bilateral oophorectomy
(removal of ovaries), which is often, but not always, done in conjunction with removal of the Fallopian tubes (salpingo-oophorectomy) and uterus (hysterectomy
). Cessation of menses as a result of removal of the ovaries is called "surgical menopause". The sudden and complete drop in hormone levels usually produces extreme withdrawal symptoms such as hot flashes, etc. Removal of the uterus without removal of the ovaries, a hysterectomy, does not cause menopause, although pelvic surgery can often precipitate a somewhat earlier menopause, perhaps because of a compromised blood supply to the ovaries.
In common parlance, however, the word "menopause" usually refers not to one day, but to the whole of the menopause transition years. This span of time is also commonly called the change of life, the change, or the climacteric and more recently is known as "perimenopause", (literally meaning "around menopause").
The word menopause is also often used in popular parlance to mean all the years of postmenopause.
Regarding the presence or absence of the definite article "the", some speakers use it ("the menopause") and many don't. The article-less usage seems to be much more common judging from PubMed search results.
During perimenopause, the ovarian production of the estrogen
s and progesterone
becomes more irregular, often with wide and unpredictable fluctuations in levels. During this period, fertility diminishes, but is not considered to reach zero until the official date of menopause. The official date is determined retroactively, once 12 months have passed after the last appearance of menstrual blood.
Signs and effects of the menopause transition can begin as early as age 35, although most women become aware of the transition in their mid to late 40s, often many years after the actual beginning of the perimenopausal window. The duration of perimenopause with noticeable bodily effects can be as brief as a few years, but it is not unusual for the duration to last ten or more years. The actual duration and severity of perimenopause effects for any individual woman currently cannot be predicted in advance. Even during the process, the course of an individual woman's perimenopause can be difficult if not impossible to predict.
During the perimenopause years, many women undergo noticeable and clinically observable physical changes resulting from hormonal fluctuations. The most well-known of these is the "hot flash" or "hot flush", a sudden temporary increase in body temperature. The "flash" sensation in a "hot flash" occurs as the body temperature soars upward, reaching a peak very rapidly. The "hot" sensation in a "hot flash" is not the initial temperature rise; instead, it is a reaction to the slowness of the body's return to a more normal temperature range. A side affect of menopause is thinking that you are pregnate.
In some cases hot flashes can be so strong that they raise the body temperature multiple degrees in a very short period of time; this extreme temperature differential can cause the sufferer to feel weak and break out in heavy sweating. Despite the discomfort to the woman, hot flashes are not considered harmful by physicians. In most cases, flashes can be treated to ease extreme discomfort, using prescription medications such as hormone replacement therapy
(HRT) or SSRI medications, as well as by using over-the-counter plant estrogens and herbal remedies. Many women choose not to treat hot flashes through pharmacology
, and instead rely on dressing in ways to dissipate heat quickly (natural fibers, loose clothing, easily removable layers of lightweight garments) as well as mechanical means to aid the body in removing excess heat such as fans, drinking ice water, and staying in cool rooms.
Other common effects encountered during the perimenopausal period include mood changes, insomnia
, fatigue, and memory problems.
Menopause may, in some women, bring about a sense of loss related to the end of fertility. In addition this change often occurs at a time of life when other stressors may be present in the life of a woman:
Recent research shows that melatonin
supplementation in perimenopausal women can produce a significant improvement in thyroid function and gonadotropin levels, as well as restoring fertility and menstruation and preventing the depression associated with the menopause.
, and are not pregnant or lactating
. In women without a uterus, menopause or postmenopause is identified by a very high FSH level. Thus postmenopause is all of the time in a woman's life that take place after her last period, or more accurately, all of the time that follows the point when her ovaries become inactive.
A woman who still has her uterus (and who is neither pregnant nor lactating) can be declared to be in postmenopause once she has gone 12 full months with no flow at all, not even any spotting. When she reaches that point, she is one year into postmenopause.
The reason for this delay in declaring a woman postmenopausal is because periods are usually extremely erratic at this time of life, and therefore a reasonably long stretch of time is necessary to be sure that the cycling has actually ceased completely.
At this point a woman is considered infertile, and no longer needs to factor in the possibility of becoming pregnant. However the possibility of becoming pregnant has usually been very low (but not zero) for a number of years before this point is reached.
In women who have no uterus, and therefore have no periods, post-menopause can be determined by a blood test which can reveal the very high levels of Follicle Stimulating Hormone (FSH) that are typical of post-menopausal women.
A woman's reproductive hormone levels continue to drop and fluctuate for some time into post-menopause, so any hormone withdrawal symptoms that a woman may be experiencing do not necessarily stop right away, but may take quite some time, even several years, to disappear completely.
Any period-like flow that might occur during postmenopause, even just spotting, must be reported to a doctor. The cause may in fact be minor, but the possibility of endometrial cancer
must be checked for and eliminated.
s, a number of effects may appear. Not every woman experiences bothersome levels of these effects; the range of effects and the degree to which they appear is very variable from person to person.
Effects that are due to low estrogen levels (for example vaginal atrophy and skin drying) will continue after the menopause transition years are over; however, many effects that are caused by the extreme fluctuations in hormone levels (for example hot flashes and mood changes) usually disappear or improve significantly once the perimenopause transition is completely over. All the various possible perimenopause effects are caused by an overall drop, as well as dramatic but erratic fluctuations, in the absolute levels and relative levels of estrogens and progesterone. Some of the effects, such as formication
(crawling, itching, or tingling skin sensations), may be associated directly with hormone withdrawal
.
Both users and non-users of hormone replacement therapy
identify lack of energy as the most frequent and distressing effect. Other effects can include vasomotor
symptoms such as hot flashes and palpitation
s, psychological effects such as depression
, anxiety
, irritability, mood swing
s, memory problems and lack of concentration, and atrophic effects such as vaginal dryness and urgency of urination.
The average woman also has increasingly erratic menstrual periods, due to skipped ovulations. Typically, the timing of the flow becomes unpredictable. In addition the duration of the flow may be considerably shorter or longer than normal, and the flow itself may be significantly heavier or lighter than was previously the case, including sometimes long episodes of spotting. Early in the process it is not uncommon to have some 2-week cycles. Further into the process it is common to skip periods for months at a time, and these skipped periods may be followed by a heavier period. The number of skipped periods in a row often increases as the time of last period approaches. At the point when a woman of menopausal age has had no periods or spotting for 12 months, she is considered to be one year into post-menopause.
One way of assessing the impact on women of some of these menopause effects is the Greene Climacteric Scale
questionnaire.
Vascular instability
Urogenital atrophy, also known as vaginal atrophy, (main article: Atrophic vaginitis
)
Skeletal
Skin, soft tissue
Psychological
Sexual
Cohort studies
have reached mixed conclusions about medical conditions associated with the menopause. For example, a 2007 study found that menopause was associated with hot flashes; joint pain and muscle pain; and depressed mood
. In the same study, it appeared that menopause was not associated with poor sleep, decreased libido, and vaginal dryness
. However, in contrast to this, a 2008 study did find an association with poor sleep quality.
(FSH) and luteinizing hormone
(LH) levels because there are a decreased number of oocyte
s and follicles responding to these hormones and producing estrogen. This decrease in the production of estrogen leads to the perimenopausal symptoms of hot flashes, insomnia and mood changes. Long term effects may include osteoporosis
and vaginal atrophy.
s, making them a highly valuable resource. Selection
should therefore in theory favour a quantity of ova
that would be sufficient for the female lifespan. Over-investment is wasteful of resources, whereas under-investment leads to reduced fitness
. Human females, however, spend over one third of their lifespan in a post-reproductive phase. Possible evolutionary explanations for survival beyond reproductive maturation range from the non-adaptive to the adaptive.
A recent increase in female longevity
due to improvements in the standard of living and social care has also been suggested. It is difficult for selection, however, to favour aid from offspring to parents and grandparents Irrespective of living standards, adaptive responses are limited by physiological mechanisms. In other words senescence
is programmed and regulated by specific genes.
The mother hypothesis suggests that menopause was selected for in humans because of the extended development period of human offspring and high costs of reproduction so that mothers gain an advantage in reproductive fitness by redirecting their effort from new offspring with a low survival chance to existing children with a higher survival chance.
The Grandmother hypothesis
suggests that menopause was selected for in humans because it promotes the survival of grandchildren. According to this hypothesis, post reproductive women feed and care for children, adult nursing daughters, and grandchildren whose mothers have weaned them. Human babies require large and steady supplies of glucose to feed the growing brain. In infants in the first year of life, the brain consumes 60% of all calories, so both babies and their mothers require a dependable food supply. Some evidence suggests that hunters contribute less than half the total food budget of most hunter-gatherer societies, and often much less than half, so that foraging grandmothers can contribute substantially to the survival of grandchildren at times when mothers and fathers are unable to gather enough food for all of their children. In general, selection operates most powerfully during times of famine or other privation. So although grandmothers might not be necessary during good times, many grandchildren cannot survive without them during times of famine. Arguably, however, there is no firm consensus on the supposed evolutionary advantages (or simply neutrality) of menopause to the survival of the species in the evolutionary past.
Indeed, analysis of historical data found that the length of a female’s post-reproductive lifespan was reflected in the reproductive success of her offspring and the survival of her grandchildren. Interestingly, another study found comparative effects but only in the maternal grandmother – paternal grandmothers had a detrimental effect on infant mortality (probably due to paternity uncertainty). Differing assistance strategies for maternal and paternal grandmothers have also been demonstrated. Maternal grandmothers concentrate on offspring survival, whereas paternal grandmothers increase birth rates.
A problem concerning the grandmother hypothesis is that it requires a history of female philopatry
and yet present day evidence shows that the majority of hunter-gatherer societies are patriarchal. In addition, all variations on the mother, or grandmother effect fail to explain longevity with continued spermatogenesis in males (oldest verified paternity is 94 years, 35 years beyond the oldest documented birth attributed to females). It also fails to explain the detrimental effects of losing ovarian follicular activity, such as osteoporosis
, osteoarthritis
, Alzheimer’s disease and coronary artery disease.
In the context of menopause Hormone replacement therapy
or HRT, known in Britain
as Hormone Therapy or HT, refers to the use of estrogen plus progestin
for a woman who has an intact uterus, or estrogen alone for a woman who has had a hysterectomy
. Traditionally such therapy was provided as tablets but now is available in a range of formulations including skin patches, gels, skin sprays, subcutaneous implants and so forth. A popular alternative to conventional HRT is a synthetic hormone (derived from the Mexican yam) called tibolone
. Of the non hormonal therapies for hot flushes, some of the SSRIs appear to provide some pharmaceutical relief. Adverse effects of HRT appear to vary according to formulation and dose. See the section below on "Adverse effects of conjugated equine estrogens".
In addition to relief from hot flashes, hormone therapy can alleviate vaginal dryness, improve sleep quality and joint pain. It is also extremely effective for preventing bone loss and osteoporotic
fracture.
A woman and her doctor should carefully review her situation, her complaints and her relative risk before determining whether the benefits of HT/HRT or other therapies outweigh the risks. Until more becomes understood about the possible risks, women who elect to use hormone replacement therapy are generally well advised to take the lowest effective dose of hormones for the shortest period possible, and to question their doctors as to whether certain forms might pose fewer dangers of clots or cancer than others.
Until recently the most widely used estrogen preparation worldwide in postmenopausal women was oral conjugated equine estrogens. Other oral oestrogen preparations include synthetically derived piperazine estrone sulphate, estriol, micronised estradiol and estradiol valerate. Estradiol may also be used transdermally as a patch or gel, as a slow release percutaneous implant, and more recently as a metered dose skin spray. Intravaginal estrogens include topical estradiol in the form of a ring or pessary, estriol in pessary or cream form, dienoestrol and conjugated oestrogens in the form of creams.
Oral micronised estradiol and other oral estrogen preparations may result in up to 10 fold higher levels of circulating estrone sulphate than transdermally administered estradiol at comparable or even higher doses. This is of concern in that estrogen sensitive tissues such as breast and endometrium
have high capacity to metabolise estrone sulphate through to estradiol. Orally administered estrogen therapy also increases sex hormone binding globulin
(SHBG) to a greater extent than non orally administered estrogens. SHBG binds estrogen and testosterone in the blood and this may result in a clinically significant reduction in the bioavailability of these hormones. Thus it would seem that the prescription of oral estrogen therapy should be at the lowest available dose to minimise effects on circulating estrone sulphate and SHBG.
In those women who have no uterus (usually due to a previous hysterectomy), estrogen alone is a suitable hormone therapy and is in fact preferable to continuing to use progesterone when its function as a moderating influence on growth of the endometrium
(uterine lining) is no longer required. Women who still have a uterus need to take progesterone in addition to estrogen in order to protect against the development of endometrial hyperplasia
and endometrial carcinoma.
Oral administration of progesterone is convenient, however the oral micronised form is rapidly metabolized and inactivated in the liver, therefore high doses must be administered to achieve adequate circulating blood levels. Synthetic progestins have been developed and are prescribed to overcome this problem. Synthetic progestins are more resistant to liver metabolism, therefore lower doses can be used to achieve the desired endometrial effect. It is not uncommon for women to experience side effects with progesterone or progestin therapy. Progesterone may cause sedation so is best taken at bedtime. Synthetic progestins may cause irritability and mood changes in some women.
Conjugated equine estrogens contain estrogen molecules conjugated to hydrophilic side groups (e.g. sulfate) and are produced from the urine of pregnant Equidae (horses) mares. Premarin is the prime example of this, either alone or in Prempro, where it is combined with a synthetic progestin, medroxyprogesterone acetate.
Women had been advised for many years by numerous doctors and drug company marketing efforts (at least in the USA) that hormone therapy with conjugated equine estrogens after menopause might reduce their risk of heart disease
and prevent various aspects of aging. However, a large, randomized, controlled trial (the Women's Health Initiative
) found that women undergoing HT or HRT with conjugated equine estrogens (Premarin
), in combination with a synthetic progestin (medroxy pogesterone acetate (Premarin plus Provera, known as Prempro)), had an increased risk of breast cancer
and heart disease. An increase in breast cancer risk was not seen in the Women's Health Initiative study of conjugate estrogen alone (Premarin) versus placebo, however this study was stopped prematurely as an increased risk of stroke was observed in women treated with Premarin. Although this increase in risk was small overall, it passed the thresholds that had been established by the researchers in advance as sufficient to ethically require stopping the study.
When these results were first reported in 2002, the popular media sensationalized the story and exaggerated the risk, while the manufacturer continued to attempt to minimize the degree of risk. However most news stories failed to mention that the average age of the women in WHI was 62 years old, significantly older than the time when most women start HRT, and in fact many years into postmenopause. In order to enroll in the study, patients had to be asymptomatic
of hot flashes, so they would not know whether they received the placebo. For these reasons, WHI was not representative of generally accepted clinical practice.
The 2002 and 2003 announcements of the Women's Health Initiative of the American National Institute of Health and The Million Women Study
of the UK Cancer Research and National Health Service
collaboration respectively, that HRT treatment coincides with an increased incidence of breast cancer, heart attacks and strokes, lead to a sharp decline in HRT prescription throughout the world, which was followed by a decrease in breast cancer incidence.
On hearing the news about the WHI study, many women discontinued equine estrogens altogether, with or without their doctor's knowledge. The number of prescriptions written for Premarin and PremPro in the United States dropped within a year almost to half of their previous level. This sharp drop in usage was followed by large and successively larger drops in new breast cancer diagnoses, at six months, one year, and 18 months after the drop in Premarin and Prempro prescriptions, for a cumulative 15% drop by the end of 2003. However, the apparent meaning of this correlation is called into question by the fact that prescriptions of Prempro and Premarin fell dramatically in Canada as well, but no similarly dramatic drop in Canada's breast cancer rates was observed during the same time period. Studies designed to track the further progression of this trend after 2003 are under way, as well as studies designed to quantify how much of the drop was related to the reduced use of HT/HRT.
The WHI study results have created a new scenario for postmenopausal women.
s), that act selectively as agonists or antagonists on the estrogen receptor
s throughout the body. The most commonly prescribed SERMs are raloxifene
and tamoxifen
. Raloxifene exhibits oestrogen agonist activity on bone and lipids, and antagonist activity on breast and the endometrium. Tamoxifen is in widespread use for treatment of hormone sensitive breast cancer. Raloxifene prevents vertebral fractures in postmenopausal, osteoporotic women and reduces the risk of invasive breast cancer. While most SERMs are known to increase hot flushes, Femarelle (DT56a)
decreases them. In addition to the relieving effects on menopausal symptoms, Femarelle also increases bone mass density (BMD
), making it protective against osteoporotic fractures. These effects are achieved by an agonistic interaction with estrogen receptors in the brain and bone. On the other hand, an antagonist interaction with estrogen receptors in the breast and uterus, has no effect on these tissues.
There is more promising data from an emerging SERM treatment based on a multibotanical compound MF-101 (trade name Menerba
) can be located here.
(Paxil), Fluoxetine hydrochloride (Prozac), and Venlafaxine hydrochloride (Effexor) have been used with some success in the treatment of hot flashes, improving sleep, mood, and quality of life. Paroxetine and venlafaxine may cause nausea and insomnia. In addition, venlafaxine may cause dry mouth, constipation and decreased appetite whereas paroxetine may cause headaches. There is a theoretical reason why SSRI antidepressants might help with memory problems: they increase circulating levels of the neurotransmitter serotonin
in the brain and restore hippocampal function. Fluoxetine hydrochloride (Sarafem) is also prescribed for premenstrual dysphoric disorder
(PMDD), a mood disorder often exacerbated during perimenopause. PMDD has been found by PET scans to be associated with dysregulation of serotonin pathways in the brain and to respond quickly and powerfully to SSRIs.
being used to treat the symptoms of fibromyalgia
under the brand name Lyrica); gabapentin itself has been shown to be as effective as estrogen at reducing hot flashes.
(Catapres) are about as effective as antidepressants for hot flashes, but do not have the other mind and mood benefits of antidepressants. However they may merit special consideration by women suffering both from high blood pressure and hot flashes.
, do not simply mimic the effects of human steroidal estrogen but exhibit both similar and divergent actions. The ultimate actions of these compounds in specific cells is determined by many factors including the relative levels of the estrogen receptors ER alpha and beta and the diverse mix of coactivators and corepressors present in any given cell type. Thus they have been described to act somewhat like selective estrogen receptor modulator
s (SERMs). Effects vary according to the phytoestrogen studied, cell line, tissue, species and response being evaluated.
Systematic reviews of intervention studies question the validity of the proposed benefits of phytoestrogen supplementation, with little data in postmenopausal women to support a role for phytoestrogens as an alternative for conventional HT. Femarelle is a mixture of DT56a soy derivative and ground flaxseed at a ratio of 3:1, for oral administration. Each capsule contains 344 mg soy and 108 mg flaxseed – altogether 430 mg powder. It is being promoted for the treatment of menopause and prevention of bone loss and has also been described as having SERM qualities, thereby reducing the safety risks involved in estrogenic-like treatments. In 2008 the European Food Safety Authority concluded that "a cause and effect relationship has not been established between the consumption of Femarelle® and increased BMD, increased bone formation, or decreased risk of osteoporosis or other bone disorders in post-menopausal women.".
In the area of complementary and alternative therapies, acupuncture
and acupressure treatments are promising. Numerous studies indicate positive effects, especially on hot flashes
but also others showing no positive effects of acupuncture regarding menopause.
There are regular claims that soy isoflavones are beneficial concerning menopause. However, one study indicated that soy isoflavones did not improve or appreciably affect cognitive functioning in postmenopausal women.
Other remedies which work in some studies, but in other studies appear to be no better than a placebo, include red clover
isoflavone extracts and black cohosh. Black cohosh (Cimicifuga racemosa, also known as Actaea racemosa) is a North American native plant. It has common usage internationally for the treatment of hot flushes and sweats experienced by postmenopausal women. However, study results do not support a benefit of black cohosh for the treatment of menopausal symptoms. Black cohosh has been associated with reports of acute liver toxicity and a concern has been raised regarding the stimulation of pre-existing breast cancer based on an animal study.
More promising data from an emerging treatment comprised of a multibotanical compound MF-101 (trade name Menerba) can be located here Menerba
which hangs over this subject. As a result, a woman who happens to undergo a strong perimenopause with a large number of different effects, may become confused and anxious, fearing that something abnormal is happening to her. There is a strong need for more information and more education on this subject.
Ethnicity and geographical location also play a role in the experience of menopause. U.S. women of different ethnicities report significantly different types of menopausal effects. One major study found Caucasian women most likely to report what are sometimes described as psychosomatic symptoms, while African-American women were more likely to report vasomotor symptoms. Additionally, while most women in the United States have a negative view of menopause as a time of deterioration or decline, some studies seem to indicate that Asian women have an understanding of menopause that focuses on a sense of liberation, and celebrates the freedom from the risk of pregnancy. Diverging from these conclusions however, one study appeared to show that many U.S. women "experience this time as one of liberation and self-actualization."
Generally speaking, women raised in the Western world
live long enough so that a third of their life is spent in post-menopause. For some women, the menopausal transition represents a major life change, similar to menarche
in the magnitude of its social and psychological significance. Although the significance of the changes that surround menarche is fairly well recognized, in countries such as the USA, the social and psychological ramifications of the menopause transition are frequently ignored or underestimated.
show a varying degree of senescence
; rapid senescing organisms (e.g. Pacific salmon and annual plants) do not have a post-reproductive life-stage. Gradual senescence is exhibited by all placental mammalian life histories.
Menopause has been observed in several species of nonhuman primates, including rhesus monkeys, and chimpanzees. Menopause also has been reported in elephant
s, short-finned pilot whales
and other cetaceans, as well as in a variety of other vertebrate species including the guppy
, the platyfish, the budgerigar
, the laboratory rat
and mouse
, and the opossum, as well as some whales. However, with the exception of the short-finned pilot whale, such examples tend to be from captive individuals, and thus they are not necessarily representative of what happens in natural populations in the wild.
Hormone
A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...
s that cause both the creation of the uterine lining and the subsequent shedding of the uterine lining (a.k.a. the menses or the period). Menopause typically (but not always) occurs in women in midlife, during their late 40s or early 50s, and signals the end of the fertile
Fertility
Fertility is the natural capability of producing offsprings. As a measure, "fertility rate" is the number of children born per couple, person or population. Fertility differs from fecundity, which is defined as the potential for reproduction...
phase of a woman's life.
The transition from reproductive to non-reproductive is the result of a major reduction in female hormonal production by the ovaries. This transition is normally not sudden or abrupt, tends to occur over a period of years, and is a natural consequence of aging. However, for some women, the accompanying signs and effects that can occur during the menopause transition years can significantly disrupt their daily activities and sense of well-being. In addition, women who have some sort of functional disorder affecting the reproductive system (e.g., endometriosis
Endometriosis
Endometriosis is a gynecological medical condition in which cells from the lining of the uterus appear and flourish outside the uterine cavity, most commonly on the ovaries. The uterine cavity is lined by endometrial cells, which are under the influence of female hormones...
, polycystic ovary syndrome
Polycystic ovary syndrome
Polycystic ovary syndrome is one of the most common female endocrine disorders. PCOS is a complex, heterogeneous disorder of uncertain aetiology, but there is strong evidence that it can to a large degree be classified as a genetic disease....
, cancer of the reproductive organs) can go into menopause at a younger age than the normal timeframe. The functional disorders often significantly speed up the menopausal process and create more significant health problems, both physical and emotional, for the affected woman.
The word "menopause" literally means the "end of monthly cycles" from the Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
word pausis (cessation) and the root men- (month), because the word "menopause" was created to describe this change in human
Human
Humans are the only living species in the Homo genus...
females, where the end of fertility is traditionally indicated by the permanent stopping of monthly menstruation
Menstruation
Menstruation is the shedding of the uterine lining . It occurs on a regular basis in sexually reproductive-age females of certain mammal species. This article focuses on human menstruation.-Overview:...
or menses. However, menopause also exists in some other animals, many of which do not have monthly menstruation; in this case, the term mean a natural end to fertility that occurs before the end of the natural lifespan.
The date of menopause in human females is formally medically defined as the time of the last menstrual period (or menstrual flow of any amount, however small), in those women who have not had a hysterectomy
Hysterectomy
A hysterectomy is the surgical removal of the uterus, usually performed by a gynecologist. Hysterectomy may be total or partial...
. Women who have their uterus
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
removed but retain their ovaries do not immediately go into menopause, even though their periods cease. Adult women who have their ovaries removed however, go immediately into surgical menopause, no matter how young they are.
Menopause is an unavoidable change that every woman will experience, assuming she reaches middle age
Middle age
Middle age is the period of age beyond young adulthood but before the onset of old age. Various attempts have been made to define this age, which is around the third quarter of the average life span of human beings....
and beyond. It is helpful if women are able to learn what to expect and what options are available to assist the transition, if that becomes necessary. Menopause has a wide starting range, but can usually be expected in the age range of 42–58. An early menopause can be related to cigarette smoking, higher body mass index, racial and ethnic factors, illnesses, chemotherapy, radiation and the surgical removal of the uterus and/or both ovaries.
Menopause can be officially declared (in an adult woman who is not pregnant, is not lactating, and who has an intact uterus) when there has been amenorrhea (absence of any menstruation) for one complete year. However, there are many signs and effects that lead up to this point, many of which may extend well beyond it too. These include: irregular menses, vasomotor
Vasomotor
Vasomotor refers to actions upon a blood vessel which alter its diameter. More specifically, it can refer to vasodilator action and vasoconstrictor action....
instability (hot flashes and night sweats), atrophy of genitourinary
Genitourinary system
In anatomy, the genitourinary system or urogenital system is the organ system of the reproductive organs and the urinary system. These are grouped together because of their proximity to each other, their common embryological origin and the use of common pathways, like the male urethra...
tissue, increased stress, breast tenderness, vaginal dryness, forgetfulness, mood changes, and in certain cases osteoporosis
Osteoporosis
Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...
and/or heart disease. These effects are related to the hormonal changes a woman’s body is going through, and they affect each woman to a different extent. The only sign or effect that all women universally have in common is that by the end of the menopause transition every woman will have a complete cessation of menses.
Age
In the Western worldWestern world
The Western world, also known as the West and the Occident , is a term referring to the countries of Western Europe , the countries of the Americas, as well all countries of Northern and Central Europe, Australia and New Zealand...
, the most typical age range for menopause (last period from natural causes) is between the ages of 40 and 61 and the average age for last period is 51 years. The average age of natural menopause (in Australia) is 51.7 years, although this varies considerably from one individual to another. In some countries however, such as India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
and the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
, the median age of natural menopause is considerably earlier, at 44 years.
Additional factors
On average, women who smoke cigaretteCigarette
A cigarette is a small roll of finely cut tobacco leaves wrapped in a cylinder of thin paper for smoking. The cigarette is ignited at one end and allowed to smoulder; its smoke is inhaled from the other end, which is held in or to the mouth and in some cases a cigarette holder may be used as well...
s experience menopause significantly earlier than non-smokers. Women who have undergone hysterectomy with ovary conservation go through menopause on average 3.7 years earlier than the expected age.
Premature menopause
In rare cases, a woman's ovaries stop working at a very early age, ranging anywhere from the age of pubertyPuberty
Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...
to age 40, and this is known as premature ovarian failure
Premature ovarian failure
Premature Ovarian Failure , also known as premature ovarian insufficiency, primary ovarian insufficiency , premature menopause, hypergonadotropic hypogonadism, is the loss of function of the ovaries before age 40...
(POF). Spontaneous premature ovarian failure affects 1% of women by age 40, and 0.1% of women by age 30. POF is not considered to be due to the normal effects of aging. Some known causes of premature ovarian failure include autoimmune disorders, thyroid
Thyroid
The thyroid gland or simply, the thyroid , in vertebrate anatomy, is one of the largest endocrine glands. The thyroid gland is found in the neck, below the thyroid cartilage...
disease, diabetes mellitus
Diabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...
, chemotherapy
Chemotherapy
Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....
, being a carrier of the fragile X syndrome
Fragile X syndrome
Fragile X syndrome , Martin–Bell syndrome, or Escalante's syndrome , is a genetic syndrome that is the most commonly known single-gene cause of autism and the most common inherited cause of intellectual disability...
gene, and radiotherapy. However, in the majority of spontaneous cases of premature ovarian failure, the cause is unknown, i.e. it is generally idiopathic
Idiopathic
Idiopathic is an adjective used primarily in medicine meaning arising spontaneously or from an obscure or unknown cause. From Greek ἴδιος, idios + πάθος, pathos , it means approximately "a disease of its own kind". It is technically a term from nosology, the classification of disease...
.
POF is diagnosed or confirmed by high blood levels of follicle stimulating hormone (FSH) and luteinizing hormone
Luteinizing hormone
Luteinizing hormone is a hormone produced by the anterior pituitary gland. In females, an acute rise of LH called the LH surge triggers ovulation and development of the corpus luteum. In males, where LH had also been called interstitial cell-stimulating hormone , it stimulates Leydig cell...
(LH) on at least 3 occasions at least 4 weeks apart. Rates of premature menopause have been found to be significantly higher in fraternal and identical twins
TWINS
Two Wide-Angle Imaging Neutral-Atom Spectrometers are a pair of NASA instruments aboard two United States National Reconnaissance Office satellites in Molniya orbits. TWINS was designed to provide stereo images of the Earth's ring current. The first instrument, TWINS-1, was launched aboard USA-184...
; approximately 5% of twins reach menopause before the age of 40. The reasons for this are not completely understood. Transplants of ovarian tissue between identical twins have been successful in restoring fertility.
Background
The menopause transition, and postmenopause itself, is a natural life change, not a disease state or a disorder. The transition itself has a variable degree of effects: it can be a difficult time of life for some women, less so for others.Menopause is perhaps most easily understood as the opposite process to menarche
Menarche
Menarche is the first menstrual cycle, or first menstrual bleeding, in female human beings. From both social and medical perspectives it is often considered the central event of female puberty, as it signals the possibility of fertility....
, the start of the monthly periods. However, menopause in women cannot satisfactorily be defined simply as the permanent "stopping of the monthly periods", because in reality what is happening to the uterus
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
is quite secondary to the process; it is what is happening to the ovaries
Ovary
The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...
that is the crucial factor.
As an illustration of the central role that the ovaries play, it is worth pointing out that when for medical reasons the uterus has to be surgically removed (hysterectomy
Hysterectomy
A hysterectomy is the surgical removal of the uterus, usually performed by a gynecologist. Hysterectomy may be total or partial...
) in a younger woman, her periods will of course cease permanently, and the woman will be incapable of pregnancy, but as long as at least one of her ovaries is still functioning, the woman will not have reached menopause. Even without the presence of the uterus, ovulation
Ovulation
Ovulation is the process in a female's menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum . Ovulation also occurs in the estrous cycle of other female mammals, which differs in many fundamental ways from the menstrual cycle...
and the release of the sequence of reproductive hormones will continue to cycle on, until menopause is reached. In contrast to this, in circumstances where a woman's ovaries are removed (oophorectomy
Oophorectomy
Oophorectomy is the surgical removal of an ovary or ovaries. The surgery is also called ovariectomy, but this term has been traditionally used in basic science research describing the surgical removal of ovaries in laboratory animals...
), even if the uterus were to be left intact, the woman will immediately be in "surgical menopause". Surgical menopause is a menopause which is induced both suddenly and totally, by removal of both ovaries prior to the age of natural menopause.
On average, assuming there has been no surgical intervention, the first evidence of the onset of the menopause transition time is slight variations in the length of the menstrual cycle. These variations become more pronounced over time, and eventually lead to cycles that can be considerably longer or considerably shorter than usual, flow that can be significantly lighter or heavier than usual, skipped ovulations, skipped periods, and spans of time of many months with no flow at all, after which menstruation may resume. The transition is considered to be over once a woman has experienced 12 months without any menstrual bleeding at all, even though perimenopause effects may extend well beyond this point in time. The term "perimenopause", which literally means "around the menopause", refers to the menopause transition years, a span of time both before and after the date of the final episode of flow.
The hormonal context
The stages of the menopause transition have been classified according to a woman’s reported bleeding pattern, supported by changes in the pituitary follicle stimulating hormone FSHFSH
FSH may refer to:* Follicle-stimulating hormone* Fox Sports Houston, a regional Fox Sports Net affiliate station for the Houston, Texas area* Facioscapulohumeral muscular dystrophy* International Civil Aviation Organisation code for Flash Airlines...
levels.
In younger women, during a normal menstrual cycle
Menstrual cycle
The menstrual cycle is the scientific term for the physiological changes that can occur in fertile women for the purpose of sexual reproduction. This article focuses on the human menstrual cycle....
the ovaries produce estradiol
Estradiol
Estradiol is a sex hormone. Estradiol is abbreviated E2 as it has 2 hydroxyl groups in its molecular structure. Estrone has 1 and estriol has 3 . Estradiol is about 10 times as potent as estrone and about 80 times as potent as estriol in its estrogenic effect...
, testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...
and progesterone
Progesterone
Progesterone also known as P4 is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy and embryogenesis of humans and other species...
in a cyclical pattern under the control of FSH and luteinising hormone (LH) which are both produced by the pituitary gland
Pituitary gland
In vertebrate anatomy the pituitary gland, or hypophysis, is an endocrine gland about the size of a pea and weighing 0.5 g , in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain, and rests in a small, bony cavity covered by a dural fold...
. Blood estradiol
Estradiol
Estradiol is a sex hormone. Estradiol is abbreviated E2 as it has 2 hydroxyl groups in its molecular structure. Estrone has 1 and estriol has 3 . Estradiol is about 10 times as potent as estrone and about 80 times as potent as estriol in its estrogenic effect...
levels remain relatively unchanged, or may increase approaching the menopause, but are usually well preserved until the late perimenopause. This is presumed to be in response to elevated FSH levels. However, the menopause transition is characterized by marked, and often dramatic, variations in FSH and estradiol levels, and because of this, measurements of these hormones are not considered to be reliable guides to a woman's exact menopausal status.
Menopause is based on the natural or surgical cessation of estradiol and progesterone production by the ovaries, which are a part of the body's endocrine system
Endocrine system
In physiology, the endocrine system is a system of glands, each of which secretes a type of hormone directly into the bloodstream to regulate the body. The endocrine system is in contrast to the exocrine system, which secretes its chemicals using ducts. It derives from the Greek words "endo"...
of hormone
Hormone
A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...
production, in this case the hormones which make reproduction possible and influence sexual behavior. After menopause, estrogen continues to be produced in other tissues, notably the ovaries, but also in bone, blood vessels and even in the brain. However the dramatic fall in circulating estradiol levels at menopause impacts many tissues, from brain to skin.
In contrast to the sudden fall in estradiol during menopause, the levels of total and free testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...
, as well as dehydroepiandrosterone sulfate (DHEAS) and androstenedione
Androstenedione
Androstenedione is a 19-carbon steroid hormone produced in the adrenal glands and the gonads as an intermediate step in the biochemical pathway that produces the androgen testosterone and the estrogens estrone and estradiol.-Synthesis:Androstenedione is the common precursor of male and female sex...
appear to decline more or less steadily with age. An effect of natural menopause on circulating androgen
Androgen
Androgen, also called androgenic hormone or testoid, is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of male characteristics in vertebrates by binding to androgen receptors...
levels has not been observed. Thus specific tissue effects of natural menopause cannot be attributed to loss of androgenic hormone production. However, women who have had their ovaries surgically removed, who have had their ovaries damaged by chemotherapy or radiotherapy, or who have ovarian gonadotropin suppression, do have loss of ovarian androgen production as a result.
Menopause can be surgically induced by bilateral oophorectomy
Oophorectomy
Oophorectomy is the surgical removal of an ovary or ovaries. The surgery is also called ovariectomy, but this term has been traditionally used in basic science research describing the surgical removal of ovaries in laboratory animals...
(removal of ovaries), which is often, but not always, done in conjunction with removal of the Fallopian tubes (salpingo-oophorectomy) and uterus (hysterectomy
Hysterectomy
A hysterectomy is the surgical removal of the uterus, usually performed by a gynecologist. Hysterectomy may be total or partial...
). Cessation of menses as a result of removal of the ovaries is called "surgical menopause". The sudden and complete drop in hormone levels usually produces extreme withdrawal symptoms such as hot flashes, etc. Removal of the uterus without removal of the ovaries, a hysterectomy, does not cause menopause, although pelvic surgery can often precipitate a somewhat earlier menopause, perhaps because of a compromised blood supply to the ovaries.
Terminology
There is some overlap in the meaning of the various terms used to refer to menopause and the menopause transition years. In addition some of the terms are used differently in common parlance than they are by medical professionals.Menopause
Clinically speaking, menopause is tied to a specific date. Assuming the woman still has a uterus, menopause is defined as the day after her final episode of menstrual flow finishes. This date is fixed retrospectively, once 12 months have gone by with no menstrual flow at all. At this point a woman is considered to be a year into postmenopause, is considered to be infertile, and no longer needs to take into consideration the possibility of pregnancy.In common parlance, however, the word "menopause" usually refers not to one day, but to the whole of the menopause transition years. This span of time is also commonly called the change of life, the change, or the climacteric and more recently is known as "perimenopause", (literally meaning "around menopause").
The word menopause is also often used in popular parlance to mean all the years of postmenopause.
Regarding the presence or absence of the definite article "the", some speakers use it ("the menopause") and many don't. The article-less usage seems to be much more common judging from PubMed search results.
Perimenopause
Perimenopause is the term used to describe the menopause transition years. In women who have a uterus, perimenopause describes the years before and after the final period (although it is only possible to determine in retrospect which episode of flow was indeed the final period). As a medical convenience, perimenopause is technically defined as the time from which menses start to become irregular and FSH levels have increased, However, the hormonal changes are gradual, both in onset and in termination. Therefore the various possible perimenopause effects often start before and continue after this neatly-defined time slot.During perimenopause, the ovarian production of the estrogen
Estrogen
Estrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...
s and progesterone
Progesterone
Progesterone also known as P4 is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy and embryogenesis of humans and other species...
becomes more irregular, often with wide and unpredictable fluctuations in levels. During this period, fertility diminishes, but is not considered to reach zero until the official date of menopause. The official date is determined retroactively, once 12 months have passed after the last appearance of menstrual blood.
Signs and effects of the menopause transition can begin as early as age 35, although most women become aware of the transition in their mid to late 40s, often many years after the actual beginning of the perimenopausal window. The duration of perimenopause with noticeable bodily effects can be as brief as a few years, but it is not unusual for the duration to last ten or more years. The actual duration and severity of perimenopause effects for any individual woman currently cannot be predicted in advance. Even during the process, the course of an individual woman's perimenopause can be difficult if not impossible to predict.
During the perimenopause years, many women undergo noticeable and clinically observable physical changes resulting from hormonal fluctuations. The most well-known of these is the "hot flash" or "hot flush", a sudden temporary increase in body temperature. The "flash" sensation in a "hot flash" occurs as the body temperature soars upward, reaching a peak very rapidly. The "hot" sensation in a "hot flash" is not the initial temperature rise; instead, it is a reaction to the slowness of the body's return to a more normal temperature range. A side affect of menopause is thinking that you are pregnate.
In some cases hot flashes can be so strong that they raise the body temperature multiple degrees in a very short period of time; this extreme temperature differential can cause the sufferer to feel weak and break out in heavy sweating. Despite the discomfort to the woman, hot flashes are not considered harmful by physicians. In most cases, flashes can be treated to ease extreme discomfort, using prescription medications such as hormone replacement therapy
Hormone replacement therapy (menopause)
Hormone replacement therapy is a system of medical treatment for surgically menopausal, perimenopausal and to a lesser extent postmenopausal women...
(HRT) or SSRI medications, as well as by using over-the-counter plant estrogens and herbal remedies. Many women choose not to treat hot flashes through pharmacology
Pharmacology
Pharmacology is the branch of medicine and biology concerned with the study of drug action. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function...
, and instead rely on dressing in ways to dissipate heat quickly (natural fibers, loose clothing, easily removable layers of lightweight garments) as well as mechanical means to aid the body in removing excess heat such as fans, drinking ice water, and staying in cool rooms.
Other common effects encountered during the perimenopausal period include mood changes, insomnia
Insomnia
Insomnia is most often defined by an individual's report of sleeping difficulties. While the term is sometimes used in sleep literature to describe a disorder demonstrated by polysomnographic evidence of disturbed sleep, insomnia is often defined as a positive response to either of two questions:...
, fatigue, and memory problems.
Menopause may, in some women, bring about a sense of loss related to the end of fertility. In addition this change often occurs at a time of life when other stressors may be present in the life of a woman:
- Having to deal with caring for, and/or the death of, elderly parents
- The so-called "empty-nest syndrome" when children leave home
- The birth of grandchildren, which places people of "middle age" into a new category of "older people" (especially in those cultures where being older is a state that is not venerated but looked down on)
Recent research shows that melatonin
Melatonin
Melatonin , also known chemically as N-acetyl-5-methoxytryptamine, is a naturally occurring compound found in animals, plants, and microbes...
supplementation in perimenopausal women can produce a significant improvement in thyroid function and gonadotropin levels, as well as restoring fertility and menstruation and preventing the depression associated with the menopause.
Premenopause
Premenopause is a word used to describe the years leading up to the last period, when the levels of reproductive hormones are already becoming lower and more erratic, and the effects of hormone withdrawal may be present.Postmenopause
The term postmenopause is applied to women who have not experienced a menstrual bleed for a minimum of 12 months, assuming that they do still have a uterusUterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
, and are not pregnant or lactating
Lactation
Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process occurs in all female mammals, however it predates mammals. In humans the process of feeding milk is called breastfeeding or nursing...
. In women without a uterus, menopause or postmenopause is identified by a very high FSH level. Thus postmenopause is all of the time in a woman's life that take place after her last period, or more accurately, all of the time that follows the point when her ovaries become inactive.
A woman who still has her uterus (and who is neither pregnant nor lactating) can be declared to be in postmenopause once she has gone 12 full months with no flow at all, not even any spotting. When she reaches that point, she is one year into postmenopause.
The reason for this delay in declaring a woman postmenopausal is because periods are usually extremely erratic at this time of life, and therefore a reasonably long stretch of time is necessary to be sure that the cycling has actually ceased completely.
At this point a woman is considered infertile, and no longer needs to factor in the possibility of becoming pregnant. However the possibility of becoming pregnant has usually been very low (but not zero) for a number of years before this point is reached.
In women who have no uterus, and therefore have no periods, post-menopause can be determined by a blood test which can reveal the very high levels of Follicle Stimulating Hormone (FSH) that are typical of post-menopausal women.
A woman's reproductive hormone levels continue to drop and fluctuate for some time into post-menopause, so any hormone withdrawal symptoms that a woman may be experiencing do not necessarily stop right away, but may take quite some time, even several years, to disappear completely.
Any period-like flow that might occur during postmenopause, even just spotting, must be reported to a doctor. The cause may in fact be minor, but the possibility of endometrial cancer
Endometrial cancer
Endometrial cancer refers to several types of malignancies that arise from the endometrium, or lining, of the uterus. Endometrial cancers are the most common gynecologic cancers in the United States, with over 35,000 women diagnosed each year. The incidence is on a slow rise secondary to the...
must be checked for and eliminated.
Indications and signs
During the menopause transition years, as the body responds to the rapidly fluctuating and dropping levels of natural hormoneHormone
A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...
s, a number of effects may appear. Not every woman experiences bothersome levels of these effects; the range of effects and the degree to which they appear is very variable from person to person.
Effects that are due to low estrogen levels (for example vaginal atrophy and skin drying) will continue after the menopause transition years are over; however, many effects that are caused by the extreme fluctuations in hormone levels (for example hot flashes and mood changes) usually disappear or improve significantly once the perimenopause transition is completely over. All the various possible perimenopause effects are caused by an overall drop, as well as dramatic but erratic fluctuations, in the absolute levels and relative levels of estrogens and progesterone. Some of the effects, such as formication
Formication
Formication is the medical term for a sensation that resembles that of insects crawling on the skin. It is one specific form of a set of sensations known as paresthesia, which also include the more common prickling, tingling sensation of "pins and needles"...
(crawling, itching, or tingling skin sensations), may be associated directly with hormone withdrawal
Withdrawal
Withdrawal can refer to any sort of separation, but is most commonly used to describe the group of symptoms that occurs upon the abrupt discontinuation/separation or a decrease in dosage of the intake of medications, recreational drugs, and alcohol...
.
Both users and non-users of hormone replacement therapy
Hormone replacement therapy (menopause)
Hormone replacement therapy is a system of medical treatment for surgically menopausal, perimenopausal and to a lesser extent postmenopausal women...
identify lack of energy as the most frequent and distressing effect. Other effects can include vasomotor
Vasomotor
Vasomotor refers to actions upon a blood vessel which alter its diameter. More specifically, it can refer to vasodilator action and vasoconstrictor action....
symptoms such as hot flashes and palpitation
Palpitation
A palpitation is an abnormality of heartbeat that causes a conscious awareness of its beating, whether it is too slow, too fast, irregular, or at its normal frequency. The word may also refer to this sensation itself...
s, psychological effects such as depression
Clinical depression
Major depressive disorder is a mental disorder characterized by an all-encompassing low mood accompanied by low self-esteem, and by loss of interest or pleasure in normally enjoyable activities...
, anxiety
Anxiety
Anxiety is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness,...
, irritability, mood swing
Mood swing
-Associated disorders:Mood swings are commonly associated with mood disorders including bipolar disorder and depression. In patients with cases of bipolar disorder, the patient experiences serious mood swings that last for days or even weeks...
s, memory problems and lack of concentration, and atrophic effects such as vaginal dryness and urgency of urination.
The average woman also has increasingly erratic menstrual periods, due to skipped ovulations. Typically, the timing of the flow becomes unpredictable. In addition the duration of the flow may be considerably shorter or longer than normal, and the flow itself may be significantly heavier or lighter than was previously the case, including sometimes long episodes of spotting. Early in the process it is not uncommon to have some 2-week cycles. Further into the process it is common to skip periods for months at a time, and these skipped periods may be followed by a heavier period. The number of skipped periods in a row often increases as the time of last period approaches. At the point when a woman of menopausal age has had no periods or spotting for 12 months, she is considered to be one year into post-menopause.
One way of assessing the impact on women of some of these menopause effects is the Greene Climacteric Scale
Greene Menopause Index
The Greene Menopause Index also known as the Greene Climateric Scale is a questionnaire, a tool used by researchers to study the symptoms of menopause...
questionnaire.
Vascular instability
- Hot flashes or hot flushes, including night sweatsSleep hyperhidrosisSleep hyperhidrosis, more commonly known as the night sweats, is the occurrence of excessive sweating during sleep. The sufferer may or may not also suffer from excessive perspiration while awake....
and, in a few people, cold flashes - Possible but contentious increased risk of atherosclerosisAtherosclerosisAtherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...
- MigraineMigraineMigraine is a chronic neurological disorder characterized by moderate to severe headaches, and nausea...
- Rapid heartbeatTachycardiaTachycardia comes from the Greek words tachys and kardia . Tachycardia typically refers to a heart rate that exceeds the normal range for a resting heart rate...
Urogenital atrophy, also known as vaginal atrophy, (main article: Atrophic vaginitis
Atrophic vaginitis
Atrophic vaginitis is an inflammation of the vagina due to the thinning and shrinking of the tissues, as well as decreased lubrication...
)
- Thinning of the membranes of the vulvaVulvaThe vulva consists of the external genital organs of the female mammal. This article deals with the vulva of the human being, although the structures are similar for other mammals....
, the vaginaVaginaThe vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...
, the cervixCervixThe cervix is the lower, narrow portion of the uterus where it joins with the top end of the vagina. It is cylindrical or conical in shape and protrudes through the upper anterior vaginal wall...
, and also the outer urinary tract, along with considerable shrinking and loss in elasticity of all of the outer and inner genital areas. - ItchItchItch is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to classify it as any one type of sensory experience. Modern science has shown that itch has many similarities to pain, and while both are unpleasant sensory experiences, their behavioral response...
ing - Dryness
- BleedingBleedingBleeding, technically known as hemorrhaging or haemorrhaging is the loss of blood or blood escape from the circulatory system...
- Watery discharge
- Urinary frequencyPolyuriaPolyuria is a condition usually defined as excessive or abnormally large production or passage of urine . Frequent urination is sometimes included by definition, but is nonetheless usually an accompanying symptom...
- Urinary incontinenceUrinary incontinenceUrinary incontinence is any involuntary leakage of urine. It is a common and distressing problem, which may have a profound impact on quality of life. Urinary incontinence almost always results from an underlying treatable medical condition but is under-reported to medical practitioners...
- Urinary urgencyUrinary urgencyUrinary urgency is a sudden, compelling urge to urinate. It is often, though not necessarily, associated with urinary incontinence, polyuria, nocturia, and interstitial cystitis. It tends to increase with age...
- Increased susceptibility to inflammationInflammationInflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
and infectionInfectionAn infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
, for example vaginal candidiasisCandidiasisThrush redirects here. For the hoof infection see Thrush .Candidiasis or thrush is a fungal infection of any of the Candida species , of which Candida albicans is the most common...
, and urinary tract infectionUrinary tract infectionA urinary tract infection is a bacterial infection that affects any part of the urinary tract. Symptoms include frequent feeling and/or need to urinate, pain during urination, and cloudy urine. The main causal agent is Escherichia coli...
s
Skeletal
- Back painBack painBack pain is pain felt in the back that usually originates from the muscles, nerves, bones, joints or other structures in the spine.The pain can often be divided into neck pain, upper back pain, lower back pain or tailbone pain...
- Joint painArthralgiaArthralgia literally means joint pain; it is a symptom of injury, infection, illnesses or an allergic reaction to medication....
, Muscle painMyalgiaMyalgia means "muscle pain" and is a symptom of many diseases and disorders. The most common causes are the overuse or over-stretching of a muscle or group of muscles. Myalgia without a traumatic history is often due to viral infections... - OsteopeniaOsteopeniaOsteopenia is a condition where bone mineral density is lower than normal. It is considered by many doctors to be a precursor to osteoporosis. However, not every person diagnosed with osteopenia will develop osteoporosis...
and the risk of osteoporosisOsteoporosisOsteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...
gradually developing over time
Skin, soft tissue
- Breast atrophy
- breast tenderness +/- swelling
- Decreased elasticity of the skin
- FormicationFormicationFormication is the medical term for a sensation that resembles that of insects crawling on the skin. It is one specific form of a set of sensations known as paresthesia, which also include the more common prickling, tingling sensation of "pins and needles"...
(itching, tingling, burning, pins and needles, or sensation of ants crawling on or under the skin) - Skin thinning and becoming drier
Psychological
- DepressionDepression (mood)Depression is a state of low mood and aversion to activity that can affect a person's thoughts, behaviour, feelings and physical well-being. Depressed people may feel sad, anxious, empty, hopeless, helpless, worthless, guilty, irritable, or restless...
and/or anxietyAnxietyAnxiety is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness,... - Fatigue
- IrritabilityIrritabilityIrritability is an excessive response to stimuli. The term is used for both the physiological reaction to stimuli and for the pathological, abnormal or excessive sensitivity to stimuli; It is usually used to refer to anger or frustration....
- Memory lossMemory lossMemory loss can be partial or total and it is normal when it comes with aging. Sudden memory loss is usually a result of brain trauma and it may be permanent or temporary. When it is caused by medical conditions such as Alzheimers, the memory loss is gradual and tends to be permanent.Brain trauma...
, and problems with concentration - Mood disturbanceMood disorderMood disorder is the term designating a group of diagnoses in the Diagnostic and Statistical Manual of Mental Disorders classification system where a disturbance in the person's mood is hypothesized to be the main underlying feature...
- Sleep disturbancesSleep disorderA sleep disorder, or somnipathy, is a medical disorder of the sleep patterns of a person or animal. Some sleep disorders are serious enough to interfere with normal physical, mental and emotional functioning...
, poor quality sleep, light sleep, insomniaInsomniaInsomnia is most often defined by an individual's report of sleeping difficulties. While the term is sometimes used in sleep literature to describe a disorder demonstrated by polysomnographic evidence of disturbed sleep, insomnia is often defined as a positive response to either of two questions:...
and sleepiness
Sexual
- DyspareuniaDyspareuniaDyspareunia is painful sexual intercourse, due to medical or psychological causes. The symptom is reported almost exclusively by women, although the problem can also occur in men. The causes are often reversible, even when long-standing, but self-perpetuating pain is a factor after the original...
or painful intercourse - Decreased libidoLibidoLibido refers to a person's sex drive or desire for sexual activity. The desire for sex is an aspect of a person's sexuality, but varies enormously from one person to another, and it also varies depending on circumstances at a particular time. A person who has extremely frequent or a suddenly...
- Problems reaching orgasmOrgasmOrgasm is the peak of the plateau phase of the sexual response cycle, characterized by an intense sensation of pleasure...
- Vaginal drynessVaginal lubricationVaginal lubrication is a lubricating fluid that is naturally produced in a woman's vagina. Vaginal lubrication or moistness is present at all times, but production increases significantly during a woman's sexual arousal in anticipation of sexual intercourse...
and vaginal atrophy
Cohort studies
Cohort study
A cohort study or panel study is a form of longitudinal study used in medicine, social science, actuarial science, and ecology. It is an analysis of risk factors and follows a group of people who do not have the disease, and uses correlations to determine the absolute risk of subject contraction...
have reached mixed conclusions about medical conditions associated with the menopause. For example, a 2007 study found that menopause was associated with hot flashes; joint pain and muscle pain; and depressed mood
Depression (mood)
Depression is a state of low mood and aversion to activity that can affect a person's thoughts, behaviour, feelings and physical well-being. Depressed people may feel sad, anxious, empty, hopeless, helpless, worthless, guilty, irritable, or restless...
. In the same study, it appeared that menopause was not associated with poor sleep, decreased libido, and vaginal dryness
Vaginal lubrication
Vaginal lubrication is a lubricating fluid that is naturally produced in a woman's vagina. Vaginal lubrication or moistness is present at all times, but production increases significantly during a woman's sexual arousal in anticipation of sexual intercourse...
. However, in contrast to this, a 2008 study did find an association with poor sleep quality.
Cause
The causes of menopause can be considered from complementary proximate (mechanistic) perspectives (how it happens) or from ultimate (adaptive evolutionary) perspectives (why it happens). The latter group are hypotheses only.Proximate perspective
Natural or physiological menopause occurs as a part of a woman's normal aging process. It is the result of the eventual depletion of almost all of the oocytes and ovarian follicles in the ovaries. This causes an increase in circulating follicle stimulating hormoneFollicle-stimulating hormone
Follicle-stimulating hormone is a hormone found in humans and other animals. It is synthesized and secreted by gonadotrophs of the anterior pituitary gland. FSH regulates the development, growth, pubertal maturation, and reproductive processes of the body. FSH and Luteinizing hormone act...
(FSH) and luteinizing hormone
Luteinizing hormone
Luteinizing hormone is a hormone produced by the anterior pituitary gland. In females, an acute rise of LH called the LH surge triggers ovulation and development of the corpus luteum. In males, where LH had also been called interstitial cell-stimulating hormone , it stimulates Leydig cell...
(LH) levels because there are a decreased number of oocyte
Oocyte
An oocyte, ovocyte, or rarely ocyte, is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in the ovary during female gametogenesis. The female germ cells produce a primordial germ cell which undergoes a mitotic...
s and follicles responding to these hormones and producing estrogen. This decrease in the production of estrogen leads to the perimenopausal symptoms of hot flashes, insomnia and mood changes. Long term effects may include osteoporosis
Osteoporosis
Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...
and vaginal atrophy.
Evolutionary theories of menopause
In contrast to males, females invest more in their gameteGamete
A gamete is a cell that fuses with another cell during fertilization in organisms that reproduce sexually...
s, making them a highly valuable resource. Selection
Selection
In the context of evolution, certain traits or alleles of genes segregating within a population may be subject to selection. Under selection, individuals with advantageous or "adaptive" traits tend to be more successful than their peers reproductively—meaning they contribute more offspring to the...
should therefore in theory favour a quantity of ova
Ovum
An ovum is a haploid female reproductive cell or gamete. Both animals and embryophytes have ova. The term ovule is used for the young ovum of an animal, as well as the plant structure that carries the female gametophyte and egg cell and develops into a seed after fertilization...
that would be sufficient for the female lifespan. Over-investment is wasteful of resources, whereas under-investment leads to reduced fitness
Fitness (biology)
Fitness is a central idea in evolutionary theory. It can be defined either with respect to a genotype or to a phenotype in a given environment...
. Human females, however, spend over one third of their lifespan in a post-reproductive phase. Possible evolutionary explanations for survival beyond reproductive maturation range from the non-adaptive to the adaptive.
Non-adaptive hypotheses
The high cost of female investment in offspring may lead to physiological deteriorations that amplify susceptibility to becoming infertile. This hypothesis suggests the reproductive lifespan in humans has been optimized, but it has proven more difficult in females and thus their reproductive span is shorter. If this hypothesis were true however, age at menopause should be negatively correlated with reproductive effort and the available data does not support this.A recent increase in female longevity
Longevity
The word "longevity" is sometimes used as a synonym for "life expectancy" in demography or known as "long life", especially when it concerns someone or something lasting longer than expected ....
due to improvements in the standard of living and social care has also been suggested. It is difficult for selection, however, to favour aid from offspring to parents and grandparents Irrespective of living standards, adaptive responses are limited by physiological mechanisms. In other words senescence
Senescence
Senescence or biological aging is the change in the biology of an organism as it ages after its maturity. Such changes range from those affecting its cells and their function to those affecting the whole organism...
is programmed and regulated by specific genes.
The mother hypothesis
The mother hypothesis suggests that menopause was selected for in humans because of the extended development period of human offspring and high costs of reproduction so that mothers gain an advantage in reproductive fitness by redirecting their effort from new offspring with a low survival chance to existing children with a higher survival chance.
The grandmother hypothesis
The Grandmother hypothesis
Grandmother hypothesis
The grandmother hypothesis is a theory to explain why menopause, rare in mammal species, arose in human evolution and how a long post-fertile period could confer an evolutionary advantage....
suggests that menopause was selected for in humans because it promotes the survival of grandchildren. According to this hypothesis, post reproductive women feed and care for children, adult nursing daughters, and grandchildren whose mothers have weaned them. Human babies require large and steady supplies of glucose to feed the growing brain. In infants in the first year of life, the brain consumes 60% of all calories, so both babies and their mothers require a dependable food supply. Some evidence suggests that hunters contribute less than half the total food budget of most hunter-gatherer societies, and often much less than half, so that foraging grandmothers can contribute substantially to the survival of grandchildren at times when mothers and fathers are unable to gather enough food for all of their children. In general, selection operates most powerfully during times of famine or other privation. So although grandmothers might not be necessary during good times, many grandchildren cannot survive without them during times of famine. Arguably, however, there is no firm consensus on the supposed evolutionary advantages (or simply neutrality) of menopause to the survival of the species in the evolutionary past.
Indeed, analysis of historical data found that the length of a female’s post-reproductive lifespan was reflected in the reproductive success of her offspring and the survival of her grandchildren. Interestingly, another study found comparative effects but only in the maternal grandmother – paternal grandmothers had a detrimental effect on infant mortality (probably due to paternity uncertainty). Differing assistance strategies for maternal and paternal grandmothers have also been demonstrated. Maternal grandmothers concentrate on offspring survival, whereas paternal grandmothers increase birth rates.
A problem concerning the grandmother hypothesis is that it requires a history of female philopatry
Philopatry
Broadly, philopatry is the behaviour of remaining in, or returning to, an individual's birthplace. More specifically, in ecology philopatry is the behaviour of elder offspring sharing the parental burden in the upbringing of their siblings, a classic example of kin selection...
and yet present day evidence shows that the majority of hunter-gatherer societies are patriarchal. In addition, all variations on the mother, or grandmother effect fail to explain longevity with continued spermatogenesis in males (oldest verified paternity is 94 years, 35 years beyond the oldest documented birth attributed to females). It also fails to explain the detrimental effects of losing ovarian follicular activity, such as osteoporosis
Osteoporosis
Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...
, osteoarthritis
Osteoarthritis
Osteoarthritis also known as degenerative arthritis or degenerative joint disease, is a group of mechanical abnormalities involving degradation of joints, including articular cartilage and subchondral bone. Symptoms may include joint pain, tenderness, stiffness, locking, and sometimes an effusion...
, Alzheimer’s disease and coronary artery disease.
Management
Perimenopause is a natural stage of life. It is not a disease or a disorder, and therefore it does not automatically require any kind of medical treatment at all. However, in those cases where the physical, mental, and emotional effects of perimenopause are strong enough that they significantly disrupt the everyday life of the woman experiencing them, palliative medical therapy may sometimes be appropriate.Hormone replacement therapy
- See also Hormone replacement therapy (menopause)Hormone replacement therapy (menopause)Hormone replacement therapy is a system of medical treatment for surgically menopausal, perimenopausal and to a lesser extent postmenopausal women...
In the context of menopause Hormone replacement therapy
Hormone replacement therapy (menopause)
Hormone replacement therapy is a system of medical treatment for surgically menopausal, perimenopausal and to a lesser extent postmenopausal women...
or HRT, known in Britain
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
as Hormone Therapy or HT, refers to the use of estrogen plus progestin
Progestin
A progestin is a synthetic progestogen that has progestinic effects similar to progesterone. The two most common uses of progestins are for hormonal contraception , and to prevent endometrial hyperplasia from unopposed estrogen in hormone replacement therapy...
for a woman who has an intact uterus, or estrogen alone for a woman who has had a hysterectomy
Hysterectomy
A hysterectomy is the surgical removal of the uterus, usually performed by a gynecologist. Hysterectomy may be total or partial...
. Traditionally such therapy was provided as tablets but now is available in a range of formulations including skin patches, gels, skin sprays, subcutaneous implants and so forth. A popular alternative to conventional HRT is a synthetic hormone (derived from the Mexican yam) called tibolone
Tibolone
Tibolone is a synthetic steroid hormone drug, which is fairly non-selective in its binding profile, acting as an agonist at all five of the Type I steroid hormone receptors. It is used mainly for treatment of endometriosis, as well as hormone replacement therapy in post-menopausal women...
. Of the non hormonal therapies for hot flushes, some of the SSRIs appear to provide some pharmaceutical relief. Adverse effects of HRT appear to vary according to formulation and dose. See the section below on "Adverse effects of conjugated equine estrogens".
In addition to relief from hot flashes, hormone therapy can alleviate vaginal dryness, improve sleep quality and joint pain. It is also extremely effective for preventing bone loss and osteoporotic
Osteoporosis
Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...
fracture.
A woman and her doctor should carefully review her situation, her complaints and her relative risk before determining whether the benefits of HT/HRT or other therapies outweigh the risks. Until more becomes understood about the possible risks, women who elect to use hormone replacement therapy are generally well advised to take the lowest effective dose of hormones for the shortest period possible, and to question their doctors as to whether certain forms might pose fewer dangers of clots or cancer than others.
Until recently the most widely used estrogen preparation worldwide in postmenopausal women was oral conjugated equine estrogens. Other oral oestrogen preparations include synthetically derived piperazine estrone sulphate, estriol, micronised estradiol and estradiol valerate. Estradiol may also be used transdermally as a patch or gel, as a slow release percutaneous implant, and more recently as a metered dose skin spray. Intravaginal estrogens include topical estradiol in the form of a ring or pessary, estriol in pessary or cream form, dienoestrol and conjugated oestrogens in the form of creams.
Oral micronised estradiol and other oral estrogen preparations may result in up to 10 fold higher levels of circulating estrone sulphate than transdermally administered estradiol at comparable or even higher doses. This is of concern in that estrogen sensitive tissues such as breast and endometrium
Endometrium
-Function:The endometrium is the innermost glandular layer and functions as a lining for the uterus, preventing adhesions between the opposed walls of the myometrium, thereby maintaining the patency of the uterine cavity. During the menstrual cycle or estrous cycle, the endometrium grows to a...
have high capacity to metabolise estrone sulphate through to estradiol. Orally administered estrogen therapy also increases sex hormone binding globulin
Sex hormone binding globulin
Sex hormone-binding globulin or sex steroid-binding globulin is a glycoprotein that binds to sex hormones, to be specific, testosterone and estradiol...
(SHBG) to a greater extent than non orally administered estrogens. SHBG binds estrogen and testosterone in the blood and this may result in a clinically significant reduction in the bioavailability of these hormones. Thus it would seem that the prescription of oral estrogen therapy should be at the lowest available dose to minimise effects on circulating estrone sulphate and SHBG.
In those women who have no uterus (usually due to a previous hysterectomy), estrogen alone is a suitable hormone therapy and is in fact preferable to continuing to use progesterone when its function as a moderating influence on growth of the endometrium
Endometrium
-Function:The endometrium is the innermost glandular layer and functions as a lining for the uterus, preventing adhesions between the opposed walls of the myometrium, thereby maintaining the patency of the uterine cavity. During the menstrual cycle or estrous cycle, the endometrium grows to a...
(uterine lining) is no longer required. Women who still have a uterus need to take progesterone in addition to estrogen in order to protect against the development of endometrial hyperplasia
Endometrial hyperplasia
Endometrial hyperplasia is a condition of excessive proliferation of the cells of the endometrium, or inner lining of the uterus.Most cases of endometrial hyperplasia result from high levels of estrogens, combined with insufficient levels of the progesterone-like hormones which ordinarily...
and endometrial carcinoma.
Oral administration of progesterone is convenient, however the oral micronised form is rapidly metabolized and inactivated in the liver, therefore high doses must be administered to achieve adequate circulating blood levels. Synthetic progestins have been developed and are prescribed to overcome this problem. Synthetic progestins are more resistant to liver metabolism, therefore lower doses can be used to achieve the desired endometrial effect. It is not uncommon for women to experience side effects with progesterone or progestin therapy. Progesterone may cause sedation so is best taken at bedtime. Synthetic progestins may cause irritability and mood changes in some women.
Conjugated equine estrogens
- See also Types of Hormone Replacement Therapy
Conjugated equine estrogens contain estrogen molecules conjugated to hydrophilic side groups (e.g. sulfate) and are produced from the urine of pregnant Equidae (horses) mares. Premarin is the prime example of this, either alone or in Prempro, where it is combined with a synthetic progestin, medroxyprogesterone acetate.
Women had been advised for many years by numerous doctors and drug company marketing efforts (at least in the USA) that hormone therapy with conjugated equine estrogens after menopause might reduce their risk of heart disease
Heart disease
Heart disease, cardiac disease or cardiopathy is an umbrella term for a variety of diseases affecting the heart. , it is the leading cause of death in the United States, England, Canada and Wales, accounting for 25.4% of the total deaths in the United States.-Types:-Coronary heart disease:Coronary...
and prevent various aspects of aging. However, a large, randomized, controlled trial (the Women's Health Initiative
Women's Health Initiative
The Women's Health Initiative was initiated by the U.S. National Institutes of Health in 1991. The objective of this women's health research initiative was to conduct medical research into some of the major health problems of older women...
) found that women undergoing HT or HRT with conjugated equine estrogens (Premarin
Premarin
Premarin is the commercial name for a compound cream of vaginally administered estrogens, consisting primarily of conjugated estrogens. Isolated from mares' urine , it is manufactured by Wyeth Pharmaceuticals and has been marketed since 1942...
), in combination with a synthetic progestin (medroxy pogesterone acetate (Premarin plus Provera, known as Prempro)), had an increased risk of breast cancer
Breast cancer
Breast cancer is cancer originating from breast tissue, most commonly from the inner lining of milk ducts or the lobules that supply the ducts with milk. Cancers originating from ducts are known as ductal carcinomas; those originating from lobules are known as lobular carcinomas...
and heart disease. An increase in breast cancer risk was not seen in the Women's Health Initiative study of conjugate estrogen alone (Premarin) versus placebo, however this study was stopped prematurely as an increased risk of stroke was observed in women treated with Premarin. Although this increase in risk was small overall, it passed the thresholds that had been established by the researchers in advance as sufficient to ethically require stopping the study.
When these results were first reported in 2002, the popular media sensationalized the story and exaggerated the risk, while the manufacturer continued to attempt to minimize the degree of risk. However most news stories failed to mention that the average age of the women in WHI was 62 years old, significantly older than the time when most women start HRT, and in fact many years into postmenopause. In order to enroll in the study, patients had to be asymptomatic
Asymptomatic
In medicine, a disease is considered asymptomatic if a patient is a carrier for a disease or infection but experiences no symptoms. A condition might be asymptomatic if it fails to show the noticeable symptoms with which it is usually associated. Asymptomatic infections are also called subclinical...
of hot flashes, so they would not know whether they received the placebo. For these reasons, WHI was not representative of generally accepted clinical practice.
The 2002 and 2003 announcements of the Women's Health Initiative of the American National Institute of Health and The Million Women Study
The Million Women Study
The Million Women Study is a study of women’s health analyzing data from more than one million women aged 50 and over conducted by UK researchers. It is a collaborative project between Cancer Research UK and the National Health Service , with additional funding from the Medical Research Council...
of the UK Cancer Research and National Health Service
National Health Service
The National Health Service is the shared name of three of the four publicly funded healthcare systems in the United Kingdom. They provide a comprehensive range of health services, the vast majority of which are free at the point of use to residents of the United Kingdom...
collaboration respectively, that HRT treatment coincides with an increased incidence of breast cancer, heart attacks and strokes, lead to a sharp decline in HRT prescription throughout the world, which was followed by a decrease in breast cancer incidence.
On hearing the news about the WHI study, many women discontinued equine estrogens altogether, with or without their doctor's knowledge. The number of prescriptions written for Premarin and PremPro in the United States dropped within a year almost to half of their previous level. This sharp drop in usage was followed by large and successively larger drops in new breast cancer diagnoses, at six months, one year, and 18 months after the drop in Premarin and Prempro prescriptions, for a cumulative 15% drop by the end of 2003. However, the apparent meaning of this correlation is called into question by the fact that prescriptions of Prempro and Premarin fell dramatically in Canada as well, but no similarly dramatic drop in Canada's breast cancer rates was observed during the same time period. Studies designed to track the further progression of this trend after 2003 are under way, as well as studies designed to quantify how much of the drop was related to the reduced use of HT/HRT.
The WHI study results have created a new scenario for postmenopausal women.
Selective Estrogen Receptor Modulators
SERMs are a category of drugs, either synthetically produced or derived from a botanical source (PhytosermPhytoserm
PhytoSERM are botanically derived substances that possess SERM qualities, similar to synthetically manufactured drugs of the same category.-Mechanism of action:...
s), that act selectively as agonists or antagonists on the estrogen receptor
Estrogen receptor
Estrogen receptor refers to a group of receptors that are activated by the hormone 17β-estradiol . Two types of estrogen receptor exist: ER, which is a member of the nuclear hormone family of intracellular receptors, and the estrogen G protein-coupled receptor GPR30 , which is a G protein-coupled...
s throughout the body. The most commonly prescribed SERMs are raloxifene
Raloxifene
Raloxifene is an oral selective estrogen receptor modulator that has estrogenic actions on bone and anti-estrogenic actions on the uterus and breast...
and tamoxifen
Tamoxifen
Tamoxifen is an antagonist of the estrogen receptor in breast tissue via its active metabolite, hydroxytamoxifen. In other tissues such as the endometrium, it behaves as an agonist, hence tamoxifen may be characterized as a mixed agonist/antagonist...
. Raloxifene exhibits oestrogen agonist activity on bone and lipids, and antagonist activity on breast and the endometrium. Tamoxifen is in widespread use for treatment of hormone sensitive breast cancer. Raloxifene prevents vertebral fractures in postmenopausal, osteoporotic women and reduces the risk of invasive breast cancer. While most SERMs are known to increase hot flushes, Femarelle (DT56a)
Femarelle (DT56a)
Femarelle is as a selective estrogen receptor modulator for the treatment of menopause and bone health. DT56a is a standardized compound derived from soybean.-Mode of Action:...
decreases them. In addition to the relieving effects on menopausal symptoms, Femarelle also increases bone mass density (BMD
BMD
BMD can refer to several things:* BMD - Polish music producer, DJ and party promoter* Britainy Maria Dye* BMD * BMD Big Medium Drink...
), making it protective against osteoporotic fractures. These effects are achieved by an agonistic interaction with estrogen receptors in the brain and bone. On the other hand, an antagonist interaction with estrogen receptors in the breast and uterus, has no effect on these tissues.
There is more promising data from an emerging SERM treatment based on a multibotanical compound MF-101 (trade name Menerba
Menerba
Menerba is a selective estrogen receptor modulator for the treatment of hot flashes associated with menopause. Menerba, an estrogen receptor beta agonist is part of a new class of receptor sub-type Selective Estrogen Receptor Modulator , which is selective in transcriptional regulation to one of...
) can be located here.
Antidepressants
Antidepressants such as paroxetineParoxetine
Paroxetine is an SSRI antidepressant. Marketing of the drug began in 1992 by the pharmaceutical company SmithKline Beecham, now GlaxoSmithKline...
(Paxil), Fluoxetine hydrochloride (Prozac), and Venlafaxine hydrochloride (Effexor) have been used with some success in the treatment of hot flashes, improving sleep, mood, and quality of life. Paroxetine and venlafaxine may cause nausea and insomnia. In addition, venlafaxine may cause dry mouth, constipation and decreased appetite whereas paroxetine may cause headaches. There is a theoretical reason why SSRI antidepressants might help with memory problems: they increase circulating levels of the neurotransmitter serotonin
Serotonin
Serotonin or 5-hydroxytryptamine is a monoamine neurotransmitter. Biochemically derived from tryptophan, serotonin is primarily found in the gastrointestinal tract, platelets, and in the central nervous system of animals including humans...
in the brain and restore hippocampal function. Fluoxetine hydrochloride (Sarafem) is also prescribed for premenstrual dysphoric disorder
Premenstrual dysphoric disorder
Premenstrual dysphoric disorder is a severe form of premenstrual syndrome, afflicting 3% to 8% of women. It is a diagnosis associated primarily with the luteal phase of the menstrual cycle...
(PMDD), a mood disorder often exacerbated during perimenopause. PMDD has been found by PET scans to be associated with dysregulation of serotonin pathways in the brain and to respond quickly and powerfully to SSRIs.
Gabapentin
Gabapentin (sometimes called by its brand name, Neurontin) and other GABA analogs are anti-seizure medications. Several GABA analogs are prescribed off-label for a variety of other conditions (such as pregabalinPregabalin
Pregabalin is an anticonvulsant drug used for neuropathic pain and as an adjunct therapy for partial seizures with or without secondary generalization in adults. It has also been found effective for generalized anxiety disorder and is approved for this use in the European Union. It was designed...
being used to treat the symptoms of fibromyalgia
Fibromyalgia
Fibromyalgia is a medical disorder characterized by chronic widespread pain and allodynia, a heightened and painful response to pressure. It is an example of a diagnosis of exclusion...
under the brand name Lyrica); gabapentin itself has been shown to be as effective as estrogen at reducing hot flashes.
Blood pressure medicines
Blood pressure medicines including clonidineClonidine
Clonidine is a sympatholytic medication used to treat medical conditions, such as high blood pressure, some pain conditions, ADHD and anxiety/panic disorder...
(Catapres) are about as effective as antidepressants for hot flashes, but do not have the other mind and mood benefits of antidepressants. However they may merit special consideration by women suffering both from high blood pressure and hot flashes.
Alternative medicine
It is important to examine the claim that herbal remedies help relieve menopausal symptoms. Some botanical sources, referred to as phytoestrogensPhytoestrogens
Phytoestrogens are plant-derived xenoestrogens functioning as the primary female sex hormone not generated within the endocrine system but consumed by eating phytoestrogonic plants...
, do not simply mimic the effects of human steroidal estrogen but exhibit both similar and divergent actions. The ultimate actions of these compounds in specific cells is determined by many factors including the relative levels of the estrogen receptors ER alpha and beta and the diverse mix of coactivators and corepressors present in any given cell type. Thus they have been described to act somewhat like selective estrogen receptor modulator
Selective estrogen receptor modulator
Selective Estrogen Receptor Modulators are a class of compounds that act on the estrogen receptor. A characteristic that distinguishes these substances from pure receptor agonists and antagonists is that their action is different in various tissues, thereby granting the possibility to selectively...
s (SERMs). Effects vary according to the phytoestrogen studied, cell line, tissue, species and response being evaluated.
Systematic reviews of intervention studies question the validity of the proposed benefits of phytoestrogen supplementation, with little data in postmenopausal women to support a role for phytoestrogens as an alternative for conventional HT. Femarelle is a mixture of DT56a soy derivative and ground flaxseed at a ratio of 3:1, for oral administration. Each capsule contains 344 mg soy and 108 mg flaxseed – altogether 430 mg powder. It is being promoted for the treatment of menopause and prevention of bone loss and has also been described as having SERM qualities, thereby reducing the safety risks involved in estrogenic-like treatments. In 2008 the European Food Safety Authority concluded that "a cause and effect relationship has not been established between the consumption of Femarelle® and increased BMD, increased bone formation, or decreased risk of osteoporosis or other bone disorders in post-menopausal women.".
In the area of complementary and alternative therapies, acupuncture
Acupuncture
Acupuncture is a type of alternative medicine that treats patients by insertion and manipulation of solid, generally thin needles in the body....
and acupressure treatments are promising. Numerous studies indicate positive effects, especially on hot flashes
but also others showing no positive effects of acupuncture regarding menopause.
There are regular claims that soy isoflavones are beneficial concerning menopause. However, one study indicated that soy isoflavones did not improve or appreciably affect cognitive functioning in postmenopausal women.
Other remedies which work in some studies, but in other studies appear to be no better than a placebo, include red clover
Red clover
Trifolium pratense is a species of clover, native to Europe, Western Asia and northwest Africa, but planted and naturalised in many other regions....
isoflavone extracts and black cohosh. Black cohosh (Cimicifuga racemosa, also known as Actaea racemosa) is a North American native plant. It has common usage internationally for the treatment of hot flushes and sweats experienced by postmenopausal women. However, study results do not support a benefit of black cohosh for the treatment of menopausal symptoms. Black cohosh has been associated with reports of acute liver toxicity and a concern has been raised regarding the stimulation of pre-existing breast cancer based on an animal study.
More promising data from an emerging treatment comprised of a multibotanical compound MF-101 (trade name Menerba) can be located here Menerba
Menerba
Menerba is a selective estrogen receptor modulator for the treatment of hot flashes associated with menopause. Menerba, an estrogen receptor beta agonist is part of a new class of receptor sub-type Selective Estrogen Receptor Modulator , which is selective in transcriptional regulation to one of...
Education
Many women arrive at their menopause transition years without knowing anything about what they might expect, or when or how the process might happen, and how long it might take. Very often a woman has not been informed in any way about this stage of life; at least in the US, it may often be the case that she has received no information from her physician, or from her older female family members, or from her social group. In the US, there appears to be a lingering tabooTaboo
A taboo is a strong social prohibition relating to any area of human activity or social custom that is sacred and or forbidden based on moral judgment, religious beliefs and or scientific consensus. Breaking the taboo is usually considered objectionable or abhorrent by society...
which hangs over this subject. As a result, a woman who happens to undergo a strong perimenopause with a large number of different effects, may become confused and anxious, fearing that something abnormal is happening to her. There is a strong need for more information and more education on this subject.
Other therapies
- Lack of lubrication is a common problem during and after perimenopause. Vaginal moisturizers can help women with overall dryness, and lubricants can help with lubrication difficulties that may be present during intercourse. It is worth pointing out that moisturizers and lubricants are different products for different issues: some women feel unpleasantly dry all of the time apart from during sex, and they may do better with moisturizers all of the time. Those who need only lubricants are fine just using the lubrication products during intercourse.
- Low-dose prescription vaginal estrogen products such as estrogen creams are generally a safe way to use estrogen topically, in order to help vaginal thinning and dryness problems (see vaginal atrophy) while only minimally increasing the levels of estrogen in the bloodstream.
- In terms of managing hot flashes, lifestyle measures, such as drinking cold liquids, staying in cool rooms, using fans, removing excess clothing layers when a hot flash strikes, and avoiding hot flash triggers such as hot drinks, spicy foods, etc., may partially supplement (or even obviate) the use of medications for some women.
- Individual counseling or support groups can sometimes be helpful to handle sad, depressed, anxious or confused feelings women may be having as they pass through what can be for some a very challenging transition time.
- OsteoporosisOsteoporosisOsteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...
can be minimized by smoking cessationSmoking cessationSmoking cessation is the process of discontinuing the practice of inhaling a smoked substance. This article focuses exclusively on cessation of tobacco smoking; however, the methods described may apply to cessation of smoking other substances that can be difficult to stop using due to the...
, adequate vitamin DVitamin DVitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....
intake and regular weight-bearing exercise. The bisphosphate drug alendronate can help prevent loss of bone mass, reducing the risk of fractures, according to a Cochrane review of studies. This applies both to women that have suffered bone loss but have not yet suffered fractures, and women that have suffered both bone loss and fractures.
- The risk of acute myocardial infarction and other cardiovascular diseaseCardiovascular diseaseHeart disease or cardiovascular disease are the class of diseases that involve the heart or blood vessels . While the term technically refers to any disease that affects the cardiovascular system , it is usually used to refer to those related to atherosclerosis...
s rises sharply after menopause, but the risk can be reduced by managing risk factors, such as tobacco smoking, hypertension, increased blood lipids and body weight.
Society and culture
The cultural context within which a woman lives can have a significant impact on the way she experiences the menopausal transition. Within the United States, social location affects the way women perceive menopause and its related biological effects. Research indicates that whether a woman views menopause as a medical issue or an expected life change is correlated with her socio-economic status. The paradigm within which a woman considers menopause also influences the way she views it: women who understand menopause as a medical condition rate it significantly more negatively than those who view it as a life transition or a symbol of aging.Ethnicity and geographical location also play a role in the experience of menopause. U.S. women of different ethnicities report significantly different types of menopausal effects. One major study found Caucasian women most likely to report what are sometimes described as psychosomatic symptoms, while African-American women were more likely to report vasomotor symptoms. Additionally, while most women in the United States have a negative view of menopause as a time of deterioration or decline, some studies seem to indicate that Asian women have an understanding of menopause that focuses on a sense of liberation, and celebrates the freedom from the risk of pregnancy. Diverging from these conclusions however, one study appeared to show that many U.S. women "experience this time as one of liberation and self-actualization."
Generally speaking, women raised in the Western world
Western world
The Western world, also known as the West and the Occident , is a term referring to the countries of Western Europe , the countries of the Americas, as well all countries of Northern and Central Europe, Australia and New Zealand...
live long enough so that a third of their life is spent in post-menopause. For some women, the menopausal transition represents a major life change, similar to menarche
Menarche
Menarche is the first menstrual cycle, or first menstrual bleeding, in female human beings. From both social and medical perspectives it is often considered the central event of female puberty, as it signals the possibility of fertility....
in the magnitude of its social and psychological significance. Although the significance of the changes that surround menarche is fairly well recognized, in countries such as the USA, the social and psychological ramifications of the menopause transition are frequently ignored or underestimated.
In other animals
Menopause in the animal kingdom appears perhaps to be somewhat uncommon, but the presence of this phenomenon in different species has not been thoroughly researched. Life historiesBiological life cycle
A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...
show a varying degree of senescence
Senescence
Senescence or biological aging is the change in the biology of an organism as it ages after its maturity. Such changes range from those affecting its cells and their function to those affecting the whole organism...
; rapid senescing organisms (e.g. Pacific salmon and annual plants) do not have a post-reproductive life-stage. Gradual senescence is exhibited by all placental mammalian life histories.
Menopause has been observed in several species of nonhuman primates, including rhesus monkeys, and chimpanzees. Menopause also has been reported in elephant
Elephant
Elephants are large land mammals in two extant genera of the family Elephantidae: Elephas and Loxodonta, with the third genus Mammuthus extinct...
s, short-finned pilot whales
Short-finned Pilot Whale
The Short-finned Pilot Whale is one of the two species of cetacean in the genus Globicephala. It is part of the oceanic dolphin family , though its behaviour is closer to that of the larger whales....
and other cetaceans, as well as in a variety of other vertebrate species including the guppy
Guppy
The guppy , also known as the millionfish, is one of the most popular freshwater aquarium fish species in the world. It is a small member of the Poeciliidae family [females long, males long] and like all other members of the family, is live-bearing....
, the platyfish, the budgerigar
Budgerigar
The Budgerigar , also known as Common Pet Parakeet or Shell Parakeet informally nicknamed the budgie, is a small, long-tailed, seed-eating parrot, and the only species in the Australian genus Melopsittacus...
, the laboratory rat
Rat
Rats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...
and mouse
Mouse
A mouse is a small mammal belonging to the order of rodents. The best known mouse species is the common house mouse . It is also a popular pet. In some places, certain kinds of field mice are also common. This rodent is eaten by large birds such as hawks and eagles...
, and the opossum, as well as some whales. However, with the exception of the short-finned pilot whale, such examples tend to be from captive individuals, and thus they are not necessarily representative of what happens in natural populations in the wild.
See also
- AndropauseAndropauseAndropause or male menopause, sometimes colloquially called "man-opause" is a name that has been given to a menopause-like condition in aging men...
, the so-called "male menopause" - AromatherapyAromatherapyAromatherapy is a form of alternative medicine that uses volatile plant materials, known as essential oils, and other aromatic compounds for the purpose of altering a person's mind, mood, cognitive function or health....
- Atrophic vaginitisAtrophic vaginitisAtrophic vaginitis is an inflammation of the vagina due to the thinning and shrinking of the tissues, as well as decreased lubrication...
- EstrogenEstrogenEstrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...
- European Menopause and Andropause SocietyEuropean Menopause and Andropause SocietyThe European Menopause and Andropause Society is a medical association focused on the study and treatment of the climacteric in men and women...
- Follicle-stimulating hormoneFollicle-stimulating hormoneFollicle-stimulating hormone is a hormone found in humans and other animals. It is synthesized and secreted by gonadotrophs of the anterior pituitary gland. FSH regulates the development, growth, pubertal maturation, and reproductive processes of the body. FSH and Luteinizing hormone act...
- Greene Menopause IndexGreene Menopause IndexThe Greene Menopause Index also known as the Greene Climateric Scale is a questionnaire, a tool used by researchers to study the symptoms of menopause...
- Hormone replacement therapyHormone replacement therapy (menopause)Hormone replacement therapy is a system of medical treatment for surgically menopausal, perimenopausal and to a lesser extent postmenopausal women...
- HysterectomyHysterectomyA hysterectomy is the surgical removal of the uterus, usually performed by a gynecologist. Hysterectomy may be total or partial...
- Janine O'Leary CobbJanine O'Leary CobbJanine O'Leary Cobb is a women's health activist and educator, and the author of one of the first popular books on menopause intended for a mainstream audience, Understanding Menopause...
- MenarcheMenarcheMenarche is the first menstrual cycle, or first menstrual bleeding, in female human beings. From both social and medical perspectives it is often considered the central event of female puberty, as it signals the possibility of fertility....
- Menopausal Research and Info ServiceMenopausal Research and Info ServiceThe Menopausal Research & Info Service is a British medical research charity dedicated to the research into the menopause.-External links:* http://www.webhealth.co.uk/Self_Help_and_Support_Groups_R/The_Menopausal_Helpline_Limite/the_menopausal_helpline_limite.html...
- Menstrual cycleMenstrual cycleThe menstrual cycle is the scientific term for the physiological changes that can occur in fertile women for the purpose of sexual reproduction. This article focuses on the human menstrual cycle....
- MenstruationMenstruationMenstruation is the shedding of the uterine lining . It occurs on a regular basis in sexually reproductive-age females of certain mammal species. This article focuses on human menstruation.-Overview:...
- North American Menopause SocietyNorth American Menopause SocietyThe North American Menopause Society , founded in 1989, is a nonprofit multidisciplinary organization with the mission of promoting the health and quality of life of women during midlife and beyond through an understanding of menopause and healthy aging. Based in Cleveland, Ohio, NAMS has over...
, also known as NAMS - Premature menopause, also known as Premature ovarian failurePremature ovarian failurePremature Ovarian Failure , also known as premature ovarian insufficiency, primary ovarian insufficiency , premature menopause, hypergonadotropic hypogonadism, is the loss of function of the ovaries before age 40...
- ProgesteroneProgesteroneProgesterone also known as P4 is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy and embryogenesis of humans and other species...
- TestosteroneTestosteroneTestosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...
External links
- Menopause: MedlinePlus
- Menopause and Menopause Treatments
- Menopause.org, The Official Website of The North American Menopause Society