Missed Menstrual Periods (Amenorrhea)

Amenorrhea Definition

The absence of menstrual periods is called amenorrhea. Primary amenorrhea is the failure to start having a period by the age of 16. Secondary amenorrhea is more common and refers to either the temporary or permanent ending of periods in a woman who has menstruated normally in the past. Many women miss a period occasionally. Amenorrhea occurs if a woman misses three or more periods in a row.

Amenorrhea Description

The absence of menstrual periods is a symptom, not a disease. While the average age that menstruation begins is 12, the range varies. The incidence of primary amenorrhea in the United States is just 2.5%.

Some female athletes who participate in rowing, long distance running, and cycling, may notice a few missed periods. Women athletes at a particular risk for developing amenorrhea include ballerinas and gymnasts, who typically exercise strenuously and eat poorly.

Amenorrhea Causes and symptoms

Amenorrhea can have many causes. Primary amenorrhea can be the result of hormonal imbalances, psychiatric disorders, eating disorders, malnutrition, excessive thinness or fatness, rapid weight loss, body fat content too low, and excessive physical conditioning. Intense physical training prior to puberty can delay menarche (the onset of menstruation). Every year of training can delay menarche for up to five months. Some medications such as anti-depressants, tranquilizers, steroids, and heroin can induce amenorrhea.

Primary amenorrhea

However, the main cause is a delay in the beginning of puberty either from natural reasons (such as heredity or poor nutrition) or because of a problem in the endocrine system, such as a pituitary tumor or hypothyroidism. An obstructed flow tract or inflammation in the uterus may be the presenting indications of an underlying metabolic, endocrine, congenital or gynecological disorder.

Typical causes of primary amenorrhea include:

• excessive physical activity
• drastic weight loss (such as occurs in anorexia or bulimia)
• extreme obesity
• drugs (antidepressants or tranquilizers)
• chronic illness
• turner's syndrome. (A chromosomal problem in place at birth, relevant only in cases of primary amenorrhea)
• the absence of a vagina or a uterus
• imperforate hymen (lack of an opening to allow the menstrual blood through)

Secondary amenorrhea

Some of the causes of primary amenorrhea can also cause secondary amenorrhea -- strenuous physical activity, excessive weight loss, use of antidepressants or tranquilizers, in particular. In adolescents, pregnancy and stress are two major causes. Missed periods are usually caused in adolescents by stress and changes in environment. Adolescents are especially prone to irregular periods with fevers, weight loss, changes in environment, or increased physical or athletic activity. However, any cessation of periods for four months should be evaluated.

The most common cause of secondary amenorrhea is pregnancy. Also, a woman's periods may halt temporarily after she stops taking birth control pills. This temporary halt usually lasts only for a month or two, though in some cases it can last for a year or more. Secondary amenorrhea may also be related to hormonal problems related to stress, depression, anorexia nervosa or drugs, or it may be caused by any condition affecting the ovaries, such as a tumor. The cessation of menstruation also occurs permanently after menopause or a hysterectomy.

Polycystic ovary syndrome is another common cause of secondary amenorrhea. It is caused by ovaries containing many fluid filled sacs (cysts) with abnormal levels of male hormones (androgens). This condition is related to improper functioning of the pituitary gland, as it releases hormones necessary for pregnancy (leuteinizing hormones), and can cause women to develop male characteristics, such as acne and coarse body hair. If the condition is not treated, some of the androgens may convert to estrogen, and chronically high levels of estrogen may increase the chance of developing cancer of the uterine lining.

Amenorrhea Diagnosis

It may be difficult to find the cause of amenorrhea, but the exam should start with a pregnancy test; pregnancy needs to be ruled out whenever a woman's period is two to three weeks overdue. Androgen excess, estrogen deficiency, or other problems with the endocrine system need to be checked. Prolactin in the blood and the thyroid stimulating hormone (TSH) should also be checked.

The diagnosis usually includes a patient history and a physical exam (including a pelvic exam). If a woman has missed three or more periods in a row, a physician may recommend blood tests to measure hormone levels, a scan of the skull to rule out the possibility of a pituitary tumor, and ultrasound scans of the abdomen and pelvis to rule out a tumor of the adrenal gland or ovary.

Amenorrhea Treatment

If a hormonal imbalance is the problem, progesterone for one to two weeks every month or two may correct the problem. With polycystic ovary syndrome, birth control pills are often prescribed. A pituitary tumor is treated with bromocriptine, a drug that reduces certain hormone (prolactin) secretions. Weight loss may bring on a period in an obese woman. Easing up on excessive exercise and eating a proper diet may bring on periods in teen athletes. In very rare cases, surgery may be needed for women with ovarian or uterine cysts.

Amenorrhea Prognosis

Prolonged amenorrhea can lead to infertility and other medical problems such as osteoporosis (thinning of the bones). If the halt in the normal period is caused by stress or illness, periods should begin again when the stress passes or the illness is treated. Amenorrhea that occurs with discontinuing birth control pills usually go away within six to eight weeks, although it may take up to a year.

The prognosis for polycystic ovary disease depends on the severity of the symptoms and the treatment plan. Spironolactone, a drug that blocks the production of male hormones, can help in reducing body hair. If a woman wishes to become pregnant, treatment with clomiphene may be required or, on rare occasions, surgery on the ovaries.

Amenorrhea Prevention

Primary amenorrhea caused by a congenital condition cannot be prevented. In general, however, women should maintain a healthy diet, with plenty of exercise, rest, and not too much stress, avoiding smoking and substance abuse. Female athletes should be sure to eat a balanced diet and rest and exercise normally. However, many cases of amenorrhea cannot be prevented.

Resources:

Books

• Carlson, Karen J., Stephanie Eisenstat, and Ziporyn Eisenstat. The Harvard Guide to Women's Health. Cambridge, MA: Harvard University Press, 1996.

Periodicals

• Hogg, Anne Cahill. "Breaking the Cycle: Often Confused and Frustrated, Sufferers of Amenorrhea Now have Better Treatment Options." American Fitness 15, no. 4 (July-Aug. 1997): 30-4.
• Kiningham, Robert B., Barbara Apgar, and Thomas Schwenk. "Evaluation of Amenorrhea." American Family Physician 53, no. 3 (Mar. 1996): 1185-95.
• Mayo editors. "Amenorrhea: Can Athletics Disrupt a Girl's Menstrual Cycle During the Growing Years?" Mayo Clinic Nutrition Letter 2, no. 9 (Sept. 1989): 4-5.

Organizations

• American College of Obstetricians and Gynecologists. 409 12th St., S.W., P.O. Box 96920, Washington, DC 20090-6920. http://www.acog.org
• Federation of Feminist Women's Health Centers.1469 Humboldt Rd, Suite 200, Chico, CA 96928. (530) 891-1911.
• National Women's Health Network. 514 10th St. NW, Suite 400, Washington, DC 20004. (202) 628-7814. http://www.womenshealthnetwork.org

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Reviewed: 01/2006