Oligomenorrhea

Definition

Medical dictionaries define oligomenorrhea as infrequent or very light menstruation. But physicians typically apply a narrower definition, restricting the diagnosis of oligomenorrhea to women whose periods were regularly established before they developed problems with infrequent flow. With oligomenorrhea, menstrual periods occur at intervals of greater than 35 days, with only four to nine periods in a year.

Description

True oligomenorrhea can not occur until menstrual periods have been established. In the United States, 97.5% of women have begun normal menstrual cycles by age 16. The complete absence of menstruation, whether menstrual periods never start or whether they stop after having been established, is called amenorrhea. Oligomenorrhea can become amenorrhea if menstruation stops for six months or more.

It is quite common for women at the beginning and end of their reproductive lives to miss or have irregular periods. This is normal and is usually the result of imperfect coordination between the hypothalamus, the pituitary gland, and the ovaries. For no apparent reason, a few women menstruate (with ovulation occurring) on a regular schedule as infrequently as once every two months. For them that schedule is normal and not a cause for concern.

Women with polycystic ovary syndrome (PCOS) are also likely to suffer from oligomenorrhea. PCOS is a condition in which the ovaries become filled with small cysts. Women with PCOS show menstrual irregularities that range from oligomenorrhea and amenorrhea on the one hand to very heavy, irregular periods on the other. The condition affects about 6% of premenopausal women and is related to excess androgen production.

Other physical and emotional factors also cause a woman to miss periods. These include:

• emotional stress
• chronic illness
• poor nutrition
• eating disorders such as anorexia nervosa
• excessive exercise
• estrogen-secreting tumors
• illicit use of anabolic steriod drugs to enhance athletic performance

Serious ballet dancers, gymnasts, and ice skaters are especially at risk because they combine heavy activity with a diet intended to keep their weight down. One study at the University of California San Francisco found that 11% of female ultramarathon runners had amenorrhea or oligomenorrhea. This is a much higher rate than in the general population. Women's coaches are becoming more aware of the problem and are encouraging female athletes to seek medical advice. A gynecologist is the doctor most experienced in diagnosing and treating oligomenorrhea.

Causes and symptoms

Symptoms of oligomenorrhea include:

• menstrual periods at intervals of more than 35 days
• irregular menstrual periods with unpredictable flow
• some women with oligomenorrhea may have difficulty conceiving.

Oligomenorrhea that occurs in adolescents is often caused by immaturity or lack of synchronization between the hypothalamus, pituitary gland, and ovaries. The hypothalamus is part of the brain that controls body temperature, cellular metabolism, and basic functions such as eating, sleeping, and reproduction. It secretes hormones that regulate the pituitary gland.

The pituitary gland is then stimulated to produce hormones that affect growth and reproduction. At the beginning and end of a woman's reproductive life, some of these hormone messages may not be synchronized, causing menstrual irregularities.

In PCOS, oligomenorrhea is probably caused by inappropriate levels of both female and male hormones. Male hormones are produced in small quantities by all women, but in women with PCOS, levels of male hormone (androgens) are slightly higher than in other women. More recently, however, some researchers are hypothesizing that the ovaries of women with PCOS are abnormal in other respects. In 2003, a group of researchers in London reported that there are fundamental differences between the development of egg follicles in normal ovaries and follicle development in the ovaries of women with PCOS.

In athletes, models, actresses, dancers, and women with anorexia nervosa, oligomenorrhea occurs because the ratio of body fat to weight drops too low.

Diagnosis

Diagnosis of oligomenorrhea begins with the patient informing the doctor about infrequent periods. Women should seek medical treatment after three missed periods. The doctor will ask for a detailed description of the problem and take a history of how long it has existed and any patterns the patient has observed. A woman can assist the doctor in diagnosing the cause of oligomenorrhea by keeping a record of the time, frequency, length, and quantity of bleeding. She should also tell the doctor about any illnesses including longstanding conditions like diabetes mellitus. The doctor may also inquire about her diet, exercise patterns, sexual activity, contraceptive use, current medications, or past surgical procedures.

Laboratory tests

After taking the woman's history, the gynecologist or family practitioner does a pelvic examination and Pap test. To rule out specific causes of oligomenorrhea, the doctor may also do a pregnancy test and blood tests to check the level of thyroid hormone. Based on the initial test results, the doctor may want to do tests to determine the level of other hormones that play a role in reproduction.

As of 2003, more sensitive monoclonal assays have been developed for measuring hormone levels in the blood serum of women with PCOS, thus allowing earlier and more accurate diagnosis.

Treatment

Treatment of oligomenorrhea depends on the cause. In adolescents and women near menopause, oligomenorrhea usually needs no treatment. For athletes, changes in training routines and eating habits may be enough to return the woman to a regular menstrual cycle.

Most patients suffering from oligomenorrhea are treated with birth control pills. Other women, including those with PCOS, are treated with hormones. Prescribed hormones depend on which particular hormones are deficient or out of balance. When oligomenorrhea is caused by a chronic underlying disorder or disease, such as anorexia nervosa, the underlying condition must be treated for oligomenorrhea to improve.

Alternative treatment

As with conventional medicial treatments, alternative treatments are based on the cause of the condition. If a hormonal imbalance is revealed by laboratory testing, hormone replacements that are more "natural" for the body (including tri-estrogen and natural progesterone) are recommended. Glandular therapy can assist in bringing about a balance in the glands involved in the reproductive cycle, including the hypothalmus, pituitary, thyroid, ovarian, and adrenal glands. Since homeopathy and acupuncture work on deep, energetic levels to rebalance the body, these two modalities may be helpful in treating oligomenorrhea. Western and Chinese herbal medicines also can be very effective. Herbs used to treat oligomenorrhea include dong quai (Angelica sinensis), black cohosh (Cimicifuga racemosa), and chaste tree (Vitex agnus-castus). Diet and adequate nutrition, including adequate protein, essential fatty acids, whole grains, and fresh fruits and vegetables, are important for every woman, especially if deficiencies are present or if she regularly exercises very strenuously. For some women, meditation, guided imagery, and visualization can play a key role in the treatment of oligomenorrhea.

Prognosis

Many women, including those with PCOS, are successfully treated with hormones for oligomenorrhea. They have more frequent periods and begin ovulating during their menstrual cycle, restoring their fertility.

For women who do not respond to hormones or who continue to have an underlying condition that causes oligomenorrhea, the outlook is less positive. Women who have oligomenorrhea may have difficulty conceiving children and may receive fertility drugs. The absence of adequate estrogen increases risk for bone loss (osteoporosis) and cardiovascular disease. Women who do not have regular periods also are more likely to develop uterine cancer. Oligomenorrhea can become amenorrhea at any time, increasing the chance of having these complications.

Prevention

Oligomenorrhea is preventable only in women whose low body fat to weight ratio is keeping them from maintaining a regular menstrual cycle. Adequate nutrition and a less vigorous training schedules will normally prevent oligomenorrhea. When oligomenorrhea is caused by hormonal factors, it is not preventable, but it is often treatable.

Key Terms

Anorexia nervosa

A disorder of the mind and body in which people starve themselves in a desire to be thin, despite being of normal or below normal body weight for their size and age.

Cyst

An abnormal sac containing fluid or semi-solid material.

Osteoporosis

The excessive loss of calcium from the bones, causing the bones to become fragile and break easily. Women who are not menstruating are especially vulnerable to this condition because estrogen, a hormone that protects bones against calcium loss, decreases drastically after menopause.

For Your Information

Resources

Books

• Carlson, Karen J., Stephanie A. Eisenstat, and Terra Ziporyn. "Menstrual Cycle Disorders." In The Harvard Guide to Women's Health. Cambridge, MA: Harvard University Press, 1996.
• "Menstrual Abnormalities and Abnormal Uterine Bleeding." Section 18, Chapter 235 in The Merck Manual of Diagnosis and Therapy, edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 2002.

• Milsom, S. R., M. C. Sowter, M. A. Carter, et al. "LH Levels in Women with Polycystic Ovarian Syndrome: Have Modern Assays Made Them Irrelevant?" BJOG 110 (August 2003): 760-764.
• Suliman, A. M., T. P. Smith, J. Gibney, and T. J. McKenna. "Frequent Misdiagnosis and Mismanagement of Hyperprolactinemic Patients Before the Introduction of Macroprolactin Screening: Application of a New Strict Laboratory Definition of Macroprolactinemia." Clinical Chemistry 49 (September 2003): 1504-1509.
• Webber, L. J., S. Stubbs, J. Stark, et al. "Formation and Early Development of Follicles in the Polycystic Ovary." Lancet 362 (September 27, 2003): 1017-1021.

• Polycystic Ovarian Syndrome Association. P.O. Box 80517, Portland, OR 7280. (877) 775-7267. http://www.pcosupport.org

• Clinical Research Bulletin. vol. 1, no. 14. http://www.herbsinfo.com.

Source: Gale Encyclopedia of Medicine, Published December, 2002 by the Gale Group

The Essay Authors are Tish Davidson, A.M., Rebecca J. Frey, PhD.

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