IntraUterine System
Encyclopedia
The IUD with progestogen, intrauterine system (IUS), or IntraUterine Contraceptive (IUC) is a long-acting reversible hormonal contraceptive device that is placed in the uterus. An IUS has a hormone cylinder that releases a progestin
(a synthetic progestogen) called levonorgestrel
. The only brand currently available is the T-frame LNG-20 IUS, marketed as Mirena by Bayer
.
The term IUS is used in the United Kingdom
to distinguish the hormonal intrauterine contraceptive from copper-based intrauterine device
s (IUDs). In the United States, all intrauterine contraceptives are referred to with the term IUD.
The IUS can only be fitted by a qualified medical practitioner. The device should be inserted according to the manufacturer's instructions using aseptic technique
to avoid introduction of bacteria
into the uterus. Antibiotics should be given before insertion to women at high risk for endocarditis
(inflammation of the inner layer of the heart), but should not be used routinely.
During the placement appointment, the cervix
is dilated in order to sound (measure) the uterus and insert the IUS. Cervix dilation is uncomfortable and, for some women, painful. Doctors often advise women to take painkillers
before the procedure to reduce pain and discomfort, and some may even use a local anaesthetic. Insertion may be more comfortable if done midcycle, when the cervix is naturally dilated.
Once in place, the IUS is approved for birth control for up to 5 years. The cumulative 5-year pregnancy rate is estimated to be 0.7%.
(a progestin
). No single mechanism accounts for the effectiveness of the IUS in preventing pregnancy; it has several effects on the reproductive system:
to take hold of the IUS's thread and gently retracting it.
A "lost coil" occurs when the thread cannot be felt by a woman on routine checking and is not seen on speculum examination.
Various thread collector devices or simple forceps may then be used to try and grasp the device through the cervix.
In the rare cases when this is unsuccessful, an ultrasound scan may be arranged to check the position of the coil and exclude its perforation through into the abdominal cavity or its unrecognised previous expulsion. Hysteroscopy
is very rarely needed.
After removal of the IUS, normal fertility is regained after a few months, with a near-normal 80% of women able to conceive within 12 months.
Medical Eligibility Criteria for Contraceptive Use and RCOG
Faculty of Family Planning & Reproductive Health Care (FFPRHC) UK Medical Eligibility Criteria for Contraceptive Use list the following as conditions where insertion of a levonorgestrel IUS is not usually recommended or should not be used because of an unacceptable health risk.:
According to Dr. Ayman A. A. Ewies in an abstract published in Gynecological Endocrinology, 31 July 2009 the hormonal releasal of the Mirena is publicized to have a local effect but he shows that elevated levels of levonorgestrel have been found globally in some women because of various factors including low metabolic rates. He also states that weight gain is one of the major side effects.
Conditions that represent a health risk if a levonorgestrel IUS is inserted:
Conditions where the theoretical or proven risks usually outweigh the advantages of inserting a levonorgestrel IUS:
A rare but potentially serious complication is that of uterine perforation
. This may occur either during the device's insertion or from its later embedment into the myometrium
(uterine wall) and subsequent migration through to the intra-abdominal cavity. Perforation can cause internal scarring, infection, or damage to other organs, and may require surgery. Uterine perforation has been reported at rates ranging from 1 to 2.6 per 1000 insertions. It is believed that perforations are significantly underreported, however, and actual perforation rates are likely higher.
Both expulsion and perforation result in loss of contraceptive cover, and the position of the thread of the IUS should be self-checked at least once per month to verify that it is still in place.
The string(s) may be felt by some men during intercourse
. If this is problematic, the provider may tuck the strings behind the cervix, cut the strings shorter, or in more extreme cases cut the strings to level with the cervix. Cutting the strings even with the cervix prevents the woman from checking the device's correct placement, and may complicate removal.
(PID) is caused by certain sexually transmitted disease
s (STDs). PID is a serious condition that may result in infertility. IUDs can increase the risk of PID above baseline for the first 21 days after insertion and is related to the presence of an infection at the time of the insertion. STD testing should be offered at the time of an insertion. Current infection is not a reason to delay IUD insertion but if an infection is found after the insertion, the patient needs to be treated. The IUD does not need to be removed. 21 days after insertion the risk of PID returns to baseline for all women.
An animal study suggested that progestin-only hormonal contraceptives such as Mirena might increase the risk of HIV transmission, because of the thinning of the vaginal walls caused by these methods. However, a number of studies of human populations showed that progestin contraceptive use does not increase the risk of acquiring HIV.
However, like the oral contraceptive pill and other non-barrier forms of contraception, the IUS offers no protection against sexually transmitted disease.
(within 48 hours). With insertions after 48 hours, perforation of the uterus is more likely to occur when uterine involution is incomplete; involution usually completes by 4–6 weeks postpartum. Special considerations apply to women who plan to breastfeed.
Also, to allow for uterine involution, insertion of an IUS is not recommended for women having had a D&E abortion
(second-trimester abortion) within the past four weeks. Post-abortion IUD is safe and effective and has only a slightly increased risk of expulsion compared to interval insertion.
To reduce the risk of infection, insertion of an IUS is not recommended for women that have had a medical abortion
but have not yet had an ultrasound to confirm that the abortion was complete, or that have not yet had their first menstruation following the medical abortion.
Expulsion is more common when an IUS is inserted immediately after childbirth or abortion.
become lighter or, in about 20% of women, stop completely within one year of insertion. Irregular bleeding is common in the first few months after insertion, with the average user reporting 16 days of bleeding or spotting in the first month of use, but this diminishes to about four days at 12 months.
in an IUS is intended to be released at a lower dose than that used in other progestogen-only contraceptives such as the mini-pill or Norplant
(blood levels of levonorgestrel in Mirena users are half those found in Norplant users and one-tenth those found in users of levonorgestrel-only pills).
Enlarged follicles (ovarian cyst
s) have been diagnosed in about 12% of the subjects using a levonorgestrel IUS. Most of these follicles are asymptomatic, although some may be accompanied by pelvic pain or dyspareunia
. In most cases the enlarged follicles disappear spontaneously during two to three months observation. Surgical intervention is not usually required.
When using Mirena®, about 0.1% of the maternal dose of levonorgestrel can be transferred via milk to the
nursed infant.
A six-year study of breastfed infants whose mothers used a levonorgestrel-only method of birth control found the infants had increased risk of respiratory infections and eye infections, though a lower risk of neurological conditions, compared to infants whose mothers used a copper IUD. No longer-term studies have been performed to assess the long-term effects on infants of levornogestrel in breast milk.
There are conflicting recommendations about use of Mirena while breastfeeding. The U.S. FDA does not recommend any hormonal method, including Mirena, as a first choice of contraceptive for nursing mothers. The World Health Organization recommends against immediate postpartum insertion, citing increased expulsion rates. It also reports concerns about potential effects on the infant's liver and brain development in the first six weeks postpartum. However, it recommends offering Mirena as a contraceptive option beginning at six weeks postpartum even to nursing women. Planned Parenthood offers Mirena as a contraceptive option for breastfeeding women beginning at four weeks postpartum.
Levongestrel IUS is not recommended for women who have, have had, or suspect they have breast cancer.
is increased for such pregnancies, the former particularly during the second trimester; these increased risks end if the IUD is removed after pregnancy is discovered. No pattern of birth defects was found in the 35 babies for whom birth outcomes were available at the time of FDA approval.
As many as half the pregnancies that occur in Mirena users may be ectopic
. The incidence rate of ectopic pregnancies is approximately 1 per 1000 users per year.
and at the distal radius
as nonusers matched by age and BMI
. In addition, BMD measurements were similar to the expected values for women in the same age group as the participants. The authors of the study said their results were predictable, since it is well established that the main factor responsible for bone loss in women is hypoestrogenism
, and, in agreement with previous reports, they found estradiol
levels in Mirena users to be normal. However, a case report suggests osteoporosis may happen, albeit at an unknown frequency.
that was released at a rate of 65 micrograms per day. In most countries it was replaced annually, though it was approved for 18 months of use in France. It had a failure rate of 2% per year.
distributes Mirena outside the United States, while Berlex distributes it inside the United States. Both companies have worked with the Population Council, a non-profit organization that has worked with other contraceptive manufacturers (including Wyeth, maker of Norplant).
Mirena was first marketed commercially in Finland in 1990, but not approved by the U.S. Food and Drug Administration until 2000. It is intended to initially release 20 micrograms of levonorgestrel per day and may be used for five years.
, is developing a lower-dose (14 micrograms levonorgestrel per day) T-frame IUS named Femilis. Femilis would come in a smaller size (Femilis Slim) for nulliparous
women. It would be inserted without a plunger, and it is hoped its performance would be less dependent on the experience of the health care professional.
rather than being held in by a frame. It initially releases 14 micrograms of levonorgestrel per day, and may be used for at least three years. As of 2010, Fibroplant is available in Belgium from Dr Dirk Wildemeersch, the original researcher at Contrel, who carries out fittings at his office in Ghent.
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...
(a synthetic progestogen) called levonorgestrel
Levonorgestrel
Levonorgestrel is a second generation synthetic progestogen used as an active ingredient in some hormonal contraceptives.-Chemistry:...
. The only brand currently available is the T-frame LNG-20 IUS, marketed as Mirena by Bayer
Bayer
Bayer AG is a chemical and pharmaceutical company founded in Barmen , Germany in 1863. It is headquartered in Leverkusen, North Rhine-Westphalia, Germany and well known for its original brand of aspirin.-History:...
.
The term IUS is used in the United Kingdom
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...
to distinguish the hormonal intrauterine contraceptive from copper-based intrauterine device
Intrauterine device
A copper IUD is a type of intrauterine device. Most IUDs have a plastic T- or U-shaped frame which is wrapped in copper wire, with the exception of Gynefix, which is a plastic string with several copper beads, affixed to the fundus of the uterus...
s (IUDs). In the United States, all intrauterine contraceptives are referred to with the term IUD.
Clinical uses
- ContraceptionBirth controlBirth control is an umbrella term for several techniques and methods used to prevent fertilization or to interrupt pregnancy at various stages. Birth control techniques and methods include contraception , contragestion and abortion...
- menorrhagiaMenorrhagiaMenorrhagia is an abnormally heavy and prolonged menstrual period at regular intervals. Causes may be due to abnormal blood clotting, disruption of normal hormonal regulation of periods or disorders of the endometrial lining of the uterus...
(heavy periods), endometriosisEndometriosisEndometriosis 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...
, chronic pelvic pain, dysmenorrheaDysmenorrheaDysmenorrhea is a gynecological medical condition of pain during menstruation that interferes with daily activities, as defined by ACOG and others. Still, dysmenorrhea is often defined simply as menstrual pain, or at least menstrual pain that is excessive...
, and anemiaAnemiaAnemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
. In some cases, use of an IUS may prevent a need for a hysterectomyHysterectomyA hysterectomy is the surgical removal of the uterus, usually performed by a gynecologist. Hysterectomy may be total or partial...
.
Fitting
Aseptic technique
Aseptic technique refers to a procedure that is performed under sterile conditions. This includes medical and laboratory techniques, such as with microbiological cultures. It includes techniques like flame sterilization...
to avoid introduction of bacteria
Infection
An 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...
into the uterus. Antibiotics should be given before insertion to women at high risk for endocarditis
Endocarditis
Endocarditis is an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves . Other structures that may be involved include the interventricular septum, the chordae tendineae, the mural endocardium, or even on intracardiac devices...
(inflammation of the inner layer of the heart), but should not be used routinely.
During the placement appointment, the cervix
Cervix
The 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...
is dilated in order to sound (measure) the uterus and insert the IUS. Cervix dilation is uncomfortable and, for some women, painful. Doctors often advise women to take painkillers
Analgesic
An analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....
before the procedure to reduce pain and discomfort, and some may even use a local anaesthetic. Insertion may be more comfortable if done midcycle, when the cervix is naturally dilated.
Once in place, the IUS is approved for birth control for up to 5 years. The cumulative 5-year pregnancy rate is estimated to be 0.7%.
Mechanisms of birth control
The Mirena is intended to initially release a daily dose of 20 micrograms levonorgestrelLevonorgestrel
Levonorgestrel is a second generation synthetic progestogen used as an active ingredient in some hormonal contraceptives.-Chemistry:...
(a 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...
). No single mechanism accounts for the effectiveness of the IUS in preventing pregnancy; it has several effects on the reproductive system:
- Frequency of ovulationOvulationOvulation 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...
is reduced. - Cervical mucus is changed to obstruct passage of spermSpermatozoonA spermatozoon is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote...
through 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...
. - The presence of a foreign body in the uterusUterusThe 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...
prompts the release of leukocytesWhite blood cellWhite blood cells, or leukocytes , are cells of the immune system involved in defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a...
and prostaglandinProstaglandinA prostaglandin is any member of a group of lipid compounds that are derived enzymatically from fatty acids and have important functions in the animal body. Every prostaglandin contains 20 carbon atoms, including a 5-carbon ring....
s by the endometriumEndometrium-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...
, substances that are hostile to both sperm and eggsOvumAn 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...
. Some physicians believe these substances are also hostile to very early embryos.
Removal
In general, IUS removal is easiest if undertaken toward the end of a woman's period and involves a doctor or trained nurse's use of a pair of forcepsForceps
Forceps or forcipes are a handheld, hinged instrument used for grasping and holding objects. Forceps are used when fingers are too large to grasp small objects or when many objects need to be held at one time while the hands are used to perform a task. The term 'forceps' is used almost exclusively...
to take hold of the IUS's thread and gently retracting it.
A "lost coil" occurs when the thread cannot be felt by a woman on routine checking and is not seen on speculum examination.
Various thread collector devices or simple forceps may then be used to try and grasp the device through the cervix.
In the rare cases when this is unsuccessful, an ultrasound scan may be arranged to check the position of the coil and exclude its perforation through into the abdominal cavity or its unrecognised previous expulsion. Hysteroscopy
Hysteroscopy
Hysteroscopy is the inspection of the uterine cavity by endoscopy with access through the cervix. It allows for the diagnosis of intrauterine pathology and serves as a method for surgical intervention .-Method:...
is very rarely needed.
After removal of the IUS, normal fertility is regained after a few months, with a near-normal 80% of women able to conceive within 12 months.
Contraindications
The WHOWorld Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
Medical Eligibility Criteria for Contraceptive Use and RCOG
Royal College of Obstetricians and Gynaecologists
The Royal College of Obstetricians and Gynaecologists is a professional association based in the UK. Its members, including people with and without medical degrees, work in the field of obstetrics and gynaecology, that is, pregnancy, childbirth, and female sexual and reproductive health...
Faculty of Family Planning & Reproductive Health Care (FFPRHC) UK Medical Eligibility Criteria for Contraceptive Use list the following as conditions where insertion of a levonorgestrel IUS is not usually recommended or should not be used because of an unacceptable health risk.:
According to Dr. Ayman A. A. Ewies in an abstract published in Gynecological Endocrinology, 31 July 2009 the hormonal releasal of the Mirena is publicized to have a local effect but he shows that elevated levels of levonorgestrel have been found globally in some women because of various factors including low metabolic rates. He also states that weight gain is one of the major side effects.
Conditions that represent a health risk if a levonorgestrel IUS is inserted:
- weight gainWeight gainWeight gain is an increase in body weight. This can be either an increase in muscle mass, fat deposits, or excess fluids such as water.-Description:...
- PregnancyPregnancyPregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
- Postpartum puerperal sepsis
- Immediately after a septic abortionSeptic abortionA septic abortion or septic miscarriage is a form of miscarriage that is associated with a serious uterine infection. The infection carries risk of spreading infection to other parts of the body and cause septicaemia, a grave risk to the life of the woman.-Causes:A septic abortion can occur when...
- Before evaluation of unexplained vaginal bleedingVaginal bleedingVaginal bleeding refers to bleeding in females that is either a physiologic response during the non-conceptional menstrual cycle or caused by hormonal or organic problems of the reproductive system. Vaginal bleeding may occur at any age, but always needs investigation when encountered in female...
suspected of being a serious condition - MalignantMalignantMalignancy is the tendency of a medical condition, especially tumors, to become progressively worse and to potentially result in death. Malignancy in cancers is characterized by anaplasia, invasiveness, and metastasis...
gestational trophoblastic diseaseGestational trophoblastic diseaseGestational trophoblastic disease is a term used for a group of pregnancy-related tumours. These tumours are rare, and they appear when cells in the womb start to grow out of control. The cells that form gestational trophoblastic tumours are called trophoblasts and come from tissue that grows to... - Cervical cancerCervical cancerCervical cancer is malignant neoplasm of the cervix uteri or cervical area. One of the most common symptoms is abnormal vaginal bleeding, but in some cases there may be no obvious symptoms until the cancer is in its advanced stages...
(awaiting treatment) - Active liver diseaseLiver diseaseLiver disease is a broad term describing any single number of diseases affecting the liver.-Diseases:* Hepatitis, inflammation of the liver, caused mainly by various viruses but also by some poisons , autoimmunity or hereditary conditions...
: (acute viral hepatitisViral hepatitisViral hepatitis is liver inflammation due to a viral infection. It may present in acute or chronic forms. The most common causes of viral hepatitis are the five unrelated hepatotropic viruses Hepatitis A, Hepatitis B, Hepatitis C, Hepatitis D, and Hepatitis E...
, severe decompensated cirrhosisCirrhosisCirrhosis is a consequence of chronic liver disease characterized by replacement of liver tissue by fibrosis, scar tissue and regenerative nodules , leading to loss of liver function...
, benign or malignantHepatocellular carcinomaHepatocellular carcinoma is the most common type of liver cancer. Most cases of HCC are secondary to either a viral hepatitide infection or cirrhosis .Compared to other cancers, HCC is quite a rare tumor in the United States...
liver tumours) - Current or recent breast cancerBreast cancerBreast 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...
- Endometrial cancerEndometrial cancerEndometrial 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...
- Current PIDPelvic inflammatory diseasePelvic inflammatory disease is a generic term for inflammation of the uterus, fallopian tubes, and/or ovaries as it progresses to scar formation with adhesions to nearby tissues and organs. This may lead to infections. PID is a vague term and can refer to viral, fungal, parasitic, though most...
- Current purulent cervicitisCervicitisCervicitis is inflammation of the uterine cervix. Cervicitis in women has many features in common with urethritis in men and many cases are caused by sexually transmitted infections...
, chlamydial infection, or gonorrheal STIs - Known pelvic tuberculosisTuberculosisTuberculosis, MTB, or TB is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs but can also affect other parts of the body...
Conditions where the theoretical or proven risks usually outweigh the advantages of inserting a levonorgestrel IUS:
- Postpartum between 48 hours and 4 weeks (increased IUD expulsion rate with delayed postpartum insertion)
- Current deep vein thrombosis (DVT)Deep vein thrombosisDeep vein thrombosis is the formation of a blood clot in a deep vein. Deep vein thrombosis commonly affects the leg veins or the deep veins of the pelvis. Occasionally the veins of the arm are affected...
or pulmonary embolus (PE) - BenignBenignA benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...
gestational trophoblastic diseaseGestational trophoblastic diseaseGestational trophoblastic disease is a term used for a group of pregnancy-related tumours. These tumours are rare, and they appear when cells in the womb start to grow out of control. The cells that form gestational trophoblastic tumours are called trophoblasts and come from tissue that grows to... - Ovarian cancerOvarian cancerOvarian cancer is a cancerous growth arising from the ovary. Symptoms are frequently very subtle early on and may include: bloating, pelvic pain, difficulty eating and frequent urination, and are easily confused with other illnesses....
- Very high individual likelihood of exposure to gonorrheaGonorrheaGonorrhea is a common sexually transmitted infection caused by the bacterium Neisseria gonorrhoeae. The usual symptoms in men are burning with urination and penile discharge. Women, on the other hand, are asymptomatic half the time or have vaginal discharge and pelvic pain...
or chlamydial STIs - Active liver diseaseLiver diseaseLiver disease is a broad term describing any single number of diseases affecting the liver.-Diseases:* Hepatitis, inflammation of the liver, caused mainly by various viruses but also by some poisons , autoimmunity or hereditary conditions...
: (acute viral hepatitisViral hepatitisViral hepatitis is liver inflammation due to a viral infection. It may present in acute or chronic forms. The most common causes of viral hepatitis are the five unrelated hepatotropic viruses Hepatitis A, Hepatitis B, Hepatitis C, Hepatitis D, and Hepatitis E...
, severe decompensated cirrhosisCirrhosisCirrhosis is a consequence of chronic liver disease characterized by replacement of liver tissue by fibrosis, scar tissue and regenerative nodules , leading to loss of liver function...
, benign, or malignantHepatocellular carcinomaHepatocellular carcinoma is the most common type of liver cancer. Most cases of HCC are secondary to either a viral hepatitide infection or cirrhosis .Compared to other cancers, HCC is quite a rare tumor in the United States...
liver tumours)
Location of device
Following insertion, the IUS may be expelled through the cervix. An expulsion rate of 4% was observed in the manufacturer's clinical trials, with most (3%) occurring in the first year of use. Expulsion is more common in younger women, women who have not had children, and when an IUS is inserted immediately after childbirth or abortion.A rare but potentially serious complication is that of uterine perforation
Uterine perforation
Uterine perforation is a potential complication of any intrauterine procedure. It may be associated with injury to surrounding blood vessels or viscera such as the bladder or intestine. If not diagnosed at the time of the procedure it can result in massive hemorrhage or sepsis...
. This may occur either during the device's insertion or from its later embedment into the myometrium
Myometrium
The myometrium is the middle layer of the uterine wall, consisting mainly of uterine smooth muscle cells , but also of supporting stromal and vascular tissue...
(uterine wall) and subsequent migration through to the intra-abdominal cavity. Perforation can cause internal scarring, infection, or damage to other organs, and may require surgery. Uterine perforation has been reported at rates ranging from 1 to 2.6 per 1000 insertions. It is believed that perforations are significantly underreported, however, and actual perforation rates are likely higher.
Both expulsion and perforation result in loss of contraceptive cover, and the position of the thread of the IUS should be self-checked at least once per month to verify that it is still in place.
The string(s) may be felt by some men during intercourse
Sexual intercourse
Sexual intercourse, also known as copulation or coitus, commonly refers to the act in which a male's penis enters a female's vagina for the purposes of sexual pleasure or reproduction. The entities may be of opposite sexes, or they may be hermaphroditic, as is the case with snails...
. If this is problematic, the provider may tuck the strings behind the cervix, cut the strings shorter, or in more extreme cases cut the strings to level with the cervix. Cutting the strings even with the cervix prevents the woman from checking the device's correct placement, and may complicate removal.
Pelvic inflammatory disease and sexually transmitted diseases
Pelvic inflammatory diseasePelvic inflammatory disease
Pelvic inflammatory disease is a generic term for inflammation of the uterus, fallopian tubes, and/or ovaries as it progresses to scar formation with adhesions to nearby tissues and organs. This may lead to infections. PID is a vague term and can refer to viral, fungal, parasitic, though most...
(PID) is caused by certain sexually transmitted disease
Sexually transmitted disease
Sexually transmitted disease , also known as a sexually transmitted infection or venereal disease , is an illness that has a significant probability of transmission between humans by means of human sexual behavior, including vaginal intercourse, oral sex, and anal sex...
s (STDs). PID is a serious condition that may result in infertility. IUDs can increase the risk of PID above baseline for the first 21 days after insertion and is related to the presence of an infection at the time of the insertion. STD testing should be offered at the time of an insertion. Current infection is not a reason to delay IUD insertion but if an infection is found after the insertion, the patient needs to be treated. The IUD does not need to be removed. 21 days after insertion the risk of PID returns to baseline for all women.
An animal study suggested that progestin-only hormonal contraceptives such as Mirena might increase the risk of HIV transmission, because of the thinning of the vaginal walls caused by these methods. However, a number of studies of human populations showed that progestin contraceptive use does not increase the risk of acquiring HIV.
However, like the oral contraceptive pill and other non-barrier forms of contraception, the IUS offers no protection against sexually transmitted disease.
Postpartum and post-abortion insertion
An IUS may be inserted immediately postpartumPostnatal
Postnatal is the period beginning immediately after the birth of a child and extending for about six weeks. Another term would be postpartum period, as it refers to the mother...
(within 48 hours). With insertions after 48 hours, perforation of the uterus is more likely to occur when uterine involution is incomplete; involution usually completes by 4–6 weeks postpartum. Special considerations apply to women who plan to breastfeed.
Also, to allow for uterine involution, insertion of an IUS is not recommended for women having had a D&E abortion
Dilation and evacuation
Dilation and evacuation literally refers to the dilation of the cervix and surgical evacuation of the contents of the uterus...
(second-trimester abortion) within the past four weeks. Post-abortion IUD is safe and effective and has only a slightly increased risk of expulsion compared to interval insertion.
To reduce the risk of infection, insertion of an IUS is not recommended for women that have had a medical abortion
Medical abortion
A medical abortion is a type of non-surgical abortion in which abortifacient pharmaceutical drugs are used to induce abortion. An oral preparation for medical abortion is commonly referred to as an abortion pill....
but have not yet had an ultrasound to confirm that the abortion was complete, or that have not yet had their first menstruation following the medical abortion.
Expulsion is more common when an IUS is inserted immediately after childbirth or abortion.
Localized
Menstrual periodsMenstrual 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....
become lighter or, in about 20% of women, stop completely within one year of insertion. Irregular bleeding is common in the first few months after insertion, with the average user reporting 16 days of bleeding or spotting in the first month of use, but this diminishes to about four days at 12 months.
Systemic
The progestinProgestin
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...
in an IUS is intended to be released at a lower dose than that used in other progestogen-only contraceptives such as the mini-pill or Norplant
Norplant
Norplant is a form of birth control developed by the Population Council that was first approved in 1983 in Finland, where it was manufactured by Leiras Oy Pharmaceuticals...
(blood levels of levonorgestrel in Mirena users are half those found in Norplant users and one-tenth those found in users of levonorgestrel-only pills).
Enlarged follicles (ovarian cyst
Ovarian cyst
An ovarian cyst is any collection of fluid, surrounded by a very thin wall, within an ovary. Any ovarian follicle that is larger than about two centimeters is termed an ovarian cyst. An ovarian cyst can be as small as a pea, or larger than an orange....
s) have been diagnosed in about 12% of the subjects using a levonorgestrel IUS. Most of these follicles are asymptomatic, although some may be accompanied by pelvic pain or dyspareunia
Dyspareunia
Dyspareunia 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...
. In most cases the enlarged follicles disappear spontaneously during two to three months observation. Surgical intervention is not usually required.
Nursing mothers
Progestogen-only contraceptives such as an IUS are not believed to affect milk supply or infant growth. However, a study in the Mirena application for FDA approval found a lower continuation of breastfeeding at 75 days in IUS users (44%) versus copper IUD users (79%).When using Mirena®, about 0.1% of the maternal dose of levonorgestrel can be transferred via milk to the
nursed infant.
A six-year study of breastfed infants whose mothers used a levonorgestrel-only method of birth control found the infants had increased risk of respiratory infections and eye infections, though a lower risk of neurological conditions, compared to infants whose mothers used a copper IUD. No longer-term studies have been performed to assess the long-term effects on infants of levornogestrel in breast milk.
There are conflicting recommendations about use of Mirena while breastfeeding. The U.S. FDA does not recommend any hormonal method, including Mirena, as a first choice of contraceptive for nursing mothers. The World Health Organization recommends against immediate postpartum insertion, citing increased expulsion rates. It also reports concerns about potential effects on the infant's liver and brain development in the first six weeks postpartum. However, it recommends offering Mirena as a contraceptive option beginning at six weeks postpartum even to nursing women. Planned Parenthood offers Mirena as a contraceptive option for breastfeeding women beginning at four weeks postpartum.
Effect on cancer rates
The U.S. Food and Drug Administration has concluded that the carcinogenic potential of Mirena is low. According to a 1999 evaluation of the studies performed on progestin-only birth control by the International Agency for Research on Cancer, there is some evidence that progestin-only birth control reduces the risk of endometrial cancer. The IARC concluded that there is no evidence progestin-only birth control increases the risk of any cancer, though the available studies were too small to be definitively conclusive.Levongestrel IUS is not recommended for women who have, have had, or suspect they have breast cancer.
Pregnancy
Although it is one of the most effective methods of contraception, pregnancy may still occur. The risk of miscarriage or premature birthPremature birth
In humans preterm birth refers to the birth of a baby of less than 37 weeks gestational age. The cause for preterm birth is in many situations elusive and unknown; many factors appear to be associated with the development of preterm birth, making the reduction of preterm birth a challenging...
is increased for such pregnancies, the former particularly during the second trimester; these increased risks end if the IUD is removed after pregnancy is discovered. No pattern of birth defects was found in the 35 babies for whom birth outcomes were available at the time of FDA approval.
As many as half the pregnancies that occur in Mirena users may be ectopic
Ectopic pregnancy
An ectopic pregnancy, or eccysis , is a complication of pregnancy in which the embryo implants outside the uterine cavity. With rare exceptions, ectopic pregnancies are not viable. Furthermore, they are dangerous for the parent, since internal haemorrhage is a life threatening complication...
. The incidence rate of ectopic pregnancies is approximately 1 per 1000 users per year.
Bone Density
No evidence has been identified to suggest Mirena affects bone mineral density (BMD). Two small studies, limited to studying BMD in the forearm, show no decrease in BMD. One of the studies showed at 7 years of use, similar BMD at the midshaft of the ulnaUlna
The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form and runs parallel to the radius, which is shorter and smaller. In anatomical position The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form...
and at the distal radius
Radius (bone)
The radius is one of the two large bones of the forearm, the other being the ulna. It extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna, which exceeds it in length and size. It is a long bone, prism-shaped and slightly curved longitudinally...
as nonusers matched by age and BMI
Body mass index
The body mass index , or Quetelet index, is a heuristic proxy for human body fat based on an individual's weight and height. BMI does not actually measure the percentage of body fat. It was invented between 1830 and 1850 by the Belgian polymath Adolphe Quetelet during the course of developing...
. In addition, BMD measurements were similar to the expected values for women in the same age group as the participants. The authors of the study said their results were predictable, since it is well established that the main factor responsible for bone loss in women is hypoestrogenism
Hypoestrogenism
Hypoestrogenism refers to a lower than normal level of estrogen, the primary sex hormone for women. In general, lower levels of estrogen may cause differences in the breasts, genitals, urinary tract and skin....
, and, in agreement with previous reports, they found 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 in Mirena users to be normal. However, a case report suggests osteoporosis may happen, albeit at an unknown frequency.
Progestasert: 1976–2001
Progestasert was the first hormonal uterine device, developed in 1976 and manufactured until 2001. It contained progesteroneProgesterone
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...
that was released at a rate of 65 micrograms per day. In most countries it was replaced annually, though it was approved for 18 months of use in France. It had a failure rate of 2% per year.
Mirena: 1990–present
Development and studies of the Mirena Coil began in the 1970s. Schering HealthSchering
Schering AG was a research-centered German pharmaceutical company. It was founded in 1851 by Ernst Christian Friedrich Schering and merged with Bayer's pharma sector in December 2006. The company's headquarters was in Berlin-Wedding, Germany...
distributes Mirena outside the United States, while Berlex distributes it inside the United States. Both companies have worked with the Population Council, a non-profit organization that has worked with other contraceptive manufacturers (including Wyeth, maker of Norplant).
Mirena was first marketed commercially in Finland in 1990, but not approved by the U.S. Food and Drug Administration until 2000. It is intended to initially release 20 micrograms of levonorgestrel per day and may be used for five years.
Femilis
Contrel, the Belgian company that developed the frameless GyneFix IUDIntrauterine device
A copper IUD is a type of intrauterine device. Most IUDs have a plastic T- or U-shaped frame which is wrapped in copper wire, with the exception of Gynefix, which is a plastic string with several copper beads, affixed to the fundus of the uterus...
, is developing a lower-dose (14 micrograms levonorgestrel per day) T-frame IUS named Femilis. Femilis would come in a smaller size (Femilis Slim) for nulliparous
Parity (medicine)
In biology, parity is a technical term that refers to the number of times a female has given birth to a fetus.It can lead to some ambiguity for events occurring between 20 and 24 weeks, and for multiple pregnancies.-Enumeration:...
women. It would be inserted without a plunger, and it is hoped its performance would be less dependent on the experience of the health care professional.
FibroPlant-LNG
Several trials with positive results have been done on a frameless IUS called FibroPlant-LNG (also from Contrel). FibroPlant is anchored to the fundus of the uterusFundus (uterus)
The fundus of the uterus is the top portion, opposite from the cervix.Fundal height, measured from the top of the pubic bone, is routinely measured in pregnancy to determine growth rates...
rather than being held in by a frame. It initially releases 14 micrograms of levonorgestrel per day, and may be used for at least three years. As of 2010, Fibroplant is available in Belgium from Dr Dirk Wildemeersch, the original researcher at Contrel, who carries out fittings at his office in Ghent.