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• Menstrual Disorders
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Menstrual disorders

Description

An in-depth report on the causes, treatment, and prevention of menstrual cramps.

Alternative Names

Dysmenorrhea; Menorrhagia; Amenorrhea; Cramps; Heavy menstrual bleeding

Causes

Menstrual disorders can be triggered by a number of different factors, such as hormone imbalances, genetic factors, clotting disorders, and pelvic diseases.

Dysmenorrhea

• Contraction-Causing Chemicals. Powerful chemicals known as prostaglandins and arachidonic acid can induce uterine muscle contractions. Prostaglandins also play a large role in the heavy bleeding that causes dysmenorrhea.
• Abnormal Nervous System Response. Some women with primary dysmenorrhea may have autonomic nervous systems that are overly sensitive to menstrual cycle changes. The autonomic nervous system regulates heart rate and blood pressure, and it contains the pain receptors in nerve fibers in the uterus and pelvic area. As a result, women with autonomic nervous system abnormalities may have a more intense response to pain.
• Abnormalities in the Arteries in the Uterus. Impaired blood flow through the arteries in the uterus may cause severe dysmenorrhea for some women.
• Genetic Factors. Genetic factors may play an important role in over half of primary dysmenorrhea cases.
• Endometriosis. Endometriosis is a chronic and often progressive disease that develops when the tissue that lines the uterus (endometrium) grows onto other areas, such as the ovaries, bowels, or bladder. [For more information, see In-Depth Report #74 : Endometriosis].

• Uterine Fibroids. Fibroids are noncancerous growths that grow on the walls of the uterus. They can cause heavy bleeding during menstruation and cramping pain. [For more information, see In-Depth Report #73 : Uterine fibroids.]
• Other Causes . Pelvic inflammatory disease, ovarian cysts, and ectopic pregnancy. The intrauterine device (IUD) contraceptive can also cause dysmenorrhea.

Menorrhagia

Hormonal imbalances and uterine fibroids are the most common causes of menorrhagia. Other causes of menorrhagia include:

• Dysfunctional Uterine Bleeding (DUB). DUB is a general term for abnormal bleeding. It is usually caused by hormonal problems and is one of the primary causes of menorrhagia. DUB usually occurs either when girls begin to menstruate or when women approach menopause, but it can occur at any time in during a woman's reproductive life. About 90% of DUB events occur when ovulation is not occurring (anovulatory DUB). In such cases, women do not properly develop and release a mature egg. When this happens, the corpus luteum does not form. As a result, estrogen is produced continuously, causing an overgrowth of the uterus lining. The period is delayed in such cases, and when it occurs menstruation can be very heavy and prolonged. The other 10% of DUB cases occur in women who are ovulating (ovulatory DUB), but progesterone secretion is prolonged because estrogen levels are low. This causes irregular shedding of the uterine lining and break-through bleeding.
• Von Willebrand Disease and Other Bleeding Disorders . Bleeding disorders that stop blood from clotting can cause heavy menstrual bleeding. Most of these disorders have a genetic basis. Von Willebrand disease is the most common of these bleeding disorders and may be underdiagnosed in many women with unexplained menorrhagia.
• Abnormal Blood Vessel Growth . Every month, blood vessels regrow in the uterus to replace the blood-rich uterine lining lost during menstruation. Abnormalities in this growth process (called arteriogenesis or angiogenesis) may occur in some women with menorrhagia.
• Abnormalities in the Uterus . Structural problems or other abnormalities in the uterus may cause bleeding. They include uterine polyps (small benign growths in the uterus), uterine fibroids, endometriosis, adenomyosis, and miscarriage. Infections or inflammation in the vagina or pelvic area can also cause heavy bleeding.
• Medications . Certain drugs, including anticoagulants and anti-inflammatory medications, can cause heavy bleeding.
• Cancer. Uterine, ovarian, and cervical cancer can cause excessive bleeding but these are rare causes.
• Other Medical Conditions . Systemic lupus erythematosus, diabetes, pelvic inflammatory disorder, and thyroid disorders can cause heavy bleeding. Women who have migraine headaches may be more likely to experience menorrhagia and endometriosis.

Amenorrhea

Normal causes of skipped or irregular periods include pregnancy, breastfeeding, hormonal contraception, and perimenopause. Skipped periods are also common during adolescence, when it may take a while before ovulation occurs regularly. Consistently absent periods may be due to the following factors:

• Delayed Puberty . The most common cause of primary amenorrhea is delayed puberty due to some genetic factor that delays physical development.
• Weight Loss and Eating Disorders . Extreme weight loss and reduced fat stores lead to hormonal changes that include low thyroid levels (hypothyroidism) and elevated stress hormone levels (hypercortisolism). These changes effect a reduction in reproductive hormones. A syndrome known as the female athlete triad is associated with hormonal changes that occur with eating disorders in young women who excessively exercise. It comprises anorexia (severe weight loss), amenorrhea, and osteoporosis (decrease in bone density).
• Polycystic Ovarian Syndrome (PCOS). PCOS is a condition in which the ovaries produce high amounts of androgens (male hormones), particularly testosterone. PCOS occurs in about 6% of women, and amenorrhea or oligomenorrhea (infrequent menses) is quite common. According to some studies, nearly 30% of obese women with PCOS have amenorrhea.
• Elevated Prolactin Levels (Hyperprolactinemia). Prolactin is a hormone produced in the pituitary gland that stimulates breast development and milk production in association with pregnancy. High levels of prolactin (hyperprolactinemia) in women who are not pregnant or nursing can reduce gonadotropin hormones and inhibit ovulation, thus causing amenorrhea. It is the cause of between 10 - 40% of cases of secondary amenorrhea.
• Premature Ovarian Failure (POF). POF is the early depletion of follicles before age 40. In most cases it leads to premature menopause. POF is a significant cause of infertility.
• Structural Problems . In some cases, structure problems or scarring in the uterus may prevent menstrual flow. Inborn genital tract abnormalities may also cause primary amenorrhea. A specific malformation called Mullerian agenesis, in which no vagina or uterus develops, is rare but still causes about 16% of primary amenorrhea cases.
• Stress. Physical and emotional stress may block the release of luteinizing hormone, causing temporary amenorrhea

• Other Medical Conditions . Epilepsy, thyroid problems, celiac sprue, metabolic syndrome, and Cushing's disease are associated with amenorrhea.

• Review Date: 6/11/2006
• Reviewed By: Harvey Simon, M.D., Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital

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