Metrorrhagia, also known as breakthrough bleeding or spotting, is uterine bleeding at irregular intervals, particularly between the expected menstrual periods.

In some women, menstrual spotting between periods occurs as a normal and harmless part of 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...

. Some women experience acute mid-cycle abdominal pain around the time of ovulation (sometimes referred to by the German term for this phenomenon, mittelschmerz

Mittelschmerz

Mittelschmerz is a medical term for "ovulation pain" or "midcycle pain". About 20% of women experience mittelschmerz, some every cycle, some intermittently.-Symptoms and diagnosis:...

). This may also occur at the same time as menstrual spotting. The use of hormonal contraceptives, such as IUDs or oral contraceptives, can lead to breakthrough bleeding as well. If spotting continues beyond the first three cycles of oral contraceptive use, a woman should have her prescription changed to a pill containing either more 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...

 or more 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...

.

Metrorrhagia may also be a sign of an underlying disorder, such as hormone imbalance, 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...

, uterine fibroids

Uterine fibroids

A uterine fibroid is a benign tumor that originates from the smooth muscle layer and the accompanying connective tissue of the uterus.Fibroids are the most common benign tumors in...

, or cancer of the reproductive organs.

Due to repeated bleeding, it may cause significant anemia

Anemia

Anemia 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...

.

Cause

Intermittent spotting between periods can result from any of numerous reproductive system disorders.

• Dysfunctional uterine bleeding
  Dysfunctional uterine bleeding
  Dysfunctional Uterine Bleeding is abnormal genital tract bleeding based in the uterus and found in the absence of demonstrable structural or organic pathology.usually due to hormonal disturbances....
  
  
• 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...
  
  
• Adenomyosis
  Adenomyosis
  Adenomyosis is a medical condition characterized by the presence of ectopic glandular tissue found in muscle. The term adenomyosis is derived from the terms adeno- , myo- , and -osis...
  
  
• Ectopic pregnancy
  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...
  
  
• Hormone imbalance
  Hormone imbalance
  Hormones are the chemical messengers in the body that travel the bloodstream to the organs and tissues. They slowly work and affect many of the body's processes over time. Endocrine glands, which are special groups of cells, make hormones....
  
  
• 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...
  
  
• Polyp
  Polyp (medicine)
  A polyp is an abnormal growth of tissue projecting from a mucous membrane. If it is attached to the surface by a narrow elongated stalk, it is said to be pedunculated. If no stalk is present, it is said to be sessile. Polyps are commonly found in the colon, stomach, nose, sinus, urinary bladder...
  
  s
• Endometritis
  Endometritis
  Endometritis refers to inflammation of the endometrium, the inner lining of the uterus. Pathologists have traditionally classified endometritis as either acute or chronic: acute endometritis is characterized by the presence of microabscesses or neutrophils within the endometrial glands, while...
  
  
• Cervicitis
  Cervicitis
  Cervicitis 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...
  
  
• Vaginitis
  Vaginitis
  Vaginitis is an inflammation of the vagina. It can result in discharge, itching and pain, and is often associated with an irritation or infection of the vulva. It is usually due to infection. The three main kinds of vaginitis are bacterial vaginosis , vaginal candidiasis, and trichomoniasis. A...
  
  
• Diets which induce ketosis
  Ketosis
  Ketosis is a state of elevated levels of ketone bodies in the body. It is almost always generalized throughout the body, with hyperketonemia, that is, an elevated level of ketone bodies in the blood. Ketone bodies are formed by ketogenesis when the liver glycogen stores are depleted...
  
  , such as the Atkins diet
• Use of 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...
  
  -only contraceptives, such as Depo Provera
  Depo Provera
  Depo-Provera is a branded progestogen-only contraceptive, depot medroxyprogesterone acetate long acting reversible hormonal contraceptive birth control drug that is injected every 3 months...
  
  
• Cervical cancer
  Cervical cancer
  Cervical 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...
  
  
• Uterine cancer
  Uterine cancer
  The term uterine cancer may refer to any of several different types of cancer which occur in the uterus, namely:*Uterine sarcomas: sarcomas of the myometrium, or muscular layer of the uterus, are most commonly leiomyosarcomas.*Endometrial cancer:...
  
  
• Vaginal cancer
  Vaginal cancer
  Vaginal cancer is any type of cancer that forms in the tissues of the vagina. Primary vaginal cancer is rare in the general population of women and is usually a squamous carcinoma. Metastases are more common. Vaginal cancer occurs more often in women over age 50, but can occur at any age, even in...
  
  
• Cervical cancer
  Cervical cancer
  Cervical 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...
  
  
• 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...
  
  
• Primary fallopian tube cancer
• Ovarian cancer
  Ovarian cancer
  Ovarian 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....
  
  
• Uterine leiomyomas
• Enlarged uterus with menorrhea
• Irregular 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...
  
  , commonly caused by polycystic ovarian syndrome
• Pregnancy
  Pregnancy
  Pregnancy 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...
  
   (implantation bleeding, ectopic pregnancy
  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...
  
  , or incomplete miscarriage
  Miscarriage
  Miscarriage or spontaneous abortion is the spontaneous end of a pregnancy at a stage where the embryo or fetus is incapable of surviving independently, generally defined in humans at prior to 20 weeks of gestation...
  
  )
• Sexually Transmitted Infections
• Von Willebrand Disease
  Von Willebrand disease
  von Willebrand disease is the most common hereditary coagulation abnormality described in humans, although it can also be acquired as a result of other medical conditions. It arises from a qualitative or quantitative deficiency of von Willebrand factor , a multimeric protein that is required for...
  
  
• Pelvic inflammatory disease
  Pelvic 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...
  
  
• PCOS
• Change in oral contraception
• Trauma
• Sexual abuse
  Sexual abuse
  Sexual abuse, also referred to as molestation, is the forcing of undesired sexual behavior by one person upon another. When that force is immediate, of short duration, or infrequent, it is called sexual assault. The offender is referred to as a sexual abuser or molester...
  
   or rape
  Rape
  Rape is a type of sexual assault usually involving sexual intercourse, which is initiated by one or more persons against another person without that person's consent. The act may be carried out by physical force, coercion, abuse of authority or with a person who is incapable of valid consent. The...