Oligomenorrhea Health Article

Causes

Oligomenorrhea that occurs in adolescents is often caused by immaturity or lack of synchronization between the hypothalamus, pituitary gland, and ovaries. The hypothalamus is the part of the brain that controls body temperature, cellular metabolism, and such basic functions as appetite for food, the sleep/wake cycle, and reproduction. The hypothalamus also 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, resulting in menstrual irregularities.

Oligomenorrhea in PCOS is thought to be 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. Some researchers hypothesize 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 body fat drops too low compared to weight. Emotional stress related to performance anxiety may also be a factor in oligomenorrhea in these women.

Symptoms

Women with oligomenorrhea may have the following symptoms:

• menstrual periods at intervals of more than 35 days
• unusually light menstrual flow
• irregular menstrual periods with unpredictable flow
• difficulty conceiving

Young women whose oligomenorrhea is associated with the female athlete triad may have such other symptoms of the triad as frequent stress fractures, particularly in the bones of the hips, spine, or lower legs; abnormal eating patterns or extremely restrictive diets; and abnormal heart rhythms or low blood pressure.

When to call the doctor

A young woman should see her doctor as soon as she notices that a previously regular menstrual pattern has become irregular; it is not necessary to wait six months or longer to have oligomenorrhea investigated. A common rule is to consult the doctor after three missed periods.

History and physical examination

Diagnosis of oligomenorrhea begins with the patient informing the doctor about infrequent 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 recent illnesses, including longstanding conditions such as diabetes mellitus. The doctor may also inquire about the patient's diet, exercise patterns, sexual activity, contraceptive use, current medications, or past surgical procedures.

The doctor will then perform a physical examination to evaluate the patient's weight in proportion to her height, to check for signs of normal sexual development, to make sure the heart rhythm and other vital signs are normal, and to palpate (feel) the thyroid gland for evidence of swelling.

In the case of female athletes, the doctor may need to establish a relationship of trust with the patient before asking about such matters as diet, practice and workout schedules, and the use of such drugs as steroids or ephedrine. The presence of stress fractures in young women should be investigated. In some cases, the doctor may give the patients the Eating Disorder Inventory (EDI) or a similar screening questionnaire to help determine whether the patient is at risk for developing anorexia or bulimia.

Laboratory tests

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

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

Imaging studies

In some cases the doctor may order an ultrasound study of the pelvic region to check for anatomical abnormalities or x rays or a bone scan to check for bone fractures. In a few cases the doctor may order an MRI to rule out tumors affecting the hypothalamus or pituitary gland.