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.
True oligomenorrhea cannot occur until a young woman's menstrual periods have been established. In the United States, 97.5 percent of women have begun normal menstrual cycles by age 16. The complete absence of menstruation (menstrual periods never started or they stopped after having been established) is called amenorrhea. Oligomenorrhea can be redefined as amenorrhea if menstruation stops for six months or more; however, there is no universally agreed-upon cutoff point or timeline.
It is quite common for women at the beginning and end of their reproductive lives to miss periods or have them at irregular intervals. This variation 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 to very heavy and irregular periods. PCOS affects about 6 percent of premenopausal women and is related to excess androgen production.
Other physical and emotional factors also cause a woman to miss periods. These include the following:
- emotional stress
- chronic illness
- poor nutritional status
- such eating disorders as anorexia nervosa
- excessive exercise
- estrogen-secreting tumors
- abnormalities in the structure of the uterus or cervix that obstruct the outflow of menstrual fluid
- illicit use of anabolic steroid drugs to enhance athletic performance
Professional ballet dancers, gymnasts, and ice skaters are especially at risk for oligomenorrhea because they combine strenuous physical activity with a diet intended to keep their weight down. Menstrual irregularities are known to be one of the three disorders comprising the so-called "female athlete triad," the other disorders being disordered eating and osteoporosis. The triad was first formally named at the annual meeting of the American College of Sports Medicine in 1993, but doctors were aware of the combination of bone mineral loss, stress fractures, eating disorders, and participation in women's sports for several decades before the triad was named. Women's coaches have become increasingly aware of the problem since the early 1990s and are encouraging female athletes to seek medical advice.
By definition, oligomenorrhea is a health concern only for women. It is estimated that about 5 percent of women in the United States in their childbearing years experience an episode of oligomenorrhea each year. This percentage appears to be constant across racial and ethnic groups.
Oligomenorrhea related to the female athlete triad is more common in this group of women than in the general female population. One study at the University of California at San Francisco found that 11 percent of female
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.
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.
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.
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.
Treatment of oligomenorrhea depends on the cause. In adolescents and women near menopause, oligomenorrhea usually needs no treatment. For some 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 associated with an eating disorder or the female athlete triad, the underlying condition must be treated. Consultation with a psychiatrist and nutritionist is usually necessary to manage an eating disorder. Female athletes may require physical therapy or rehabilitation as well.
As with conventional medical 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 hypothalamus, pituitary, thyroid, ovarian, and adrenal glands.
Since homeopathy and acupuncture work on deep, energetic levels to rebalance the body, these two forms of therapy 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). Herbal preparations used to bring on the menstrual period are known as emmenagogues. For some women, meditation, guided imagery, and visualization can play a role in the treatment of oligomenorrhea by relieving emotional stress.
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. Female athletes at the high school or college level should consult a nutritionist to make sure that they are eating a well-balanced diet that is adequate to maintain a healthy weight for their height. Girls participating in dance or in sports that emphasize weight control or a slender body type (gymnastics, track and field, swimming, and cheerleading) are at higher risk of developing eating disorders than those that are involved in such sports as softball, weight lifting, or basketball. In some cases the athlete may be given calcium or vitamin D supplements to lower the risk of osteoporosis.
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 as teenagers may have difficulty becoming pregnant and may receive fertility drugs. The absence of adequate estrogen increases the risk of osteoporosis, repeated bone fractures, and cardiovascular disease in later life. Female athletes who develop bone loss or osteoporosis in their late teens or early twenties are at increased risk of developing arthritis as they grow older. 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.
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 less vigorous training schedules for female athletes will normally prevent oligomenorrhea. When oligomenorrhea is caused by hormonal factors, however, it is not preventable, but is usually treatable.
Oligomenorrhea in teenagers who have only recently begun to menstruate is not usually a cause for parental concern, particularly if the girl's development during puberty has been otherwise normal or if there is a family history of oligomenorrhea. Oligomenorrhea in an adolescent should be investigated, however, if the girl is heavily involved in athletics or if she is otherwise at risk for developing an eating disorder. One way that parents can help college-age athletes is to be affectionate and emotionally supportive of their daughter, as girls who are away from home for the first time or who are "loners" are particularly at risk for developing the female athlete triad during their freshman year.
Amenorrhea—The absence or abnormal stoppage of menstrual periods.
Anorexia nervosa—An eating disorder marked by an unrealistic fear of weight gain, self-starvation, and distortion of body image. It most commonly occurs in adolescent females.
Cyst—An abnormal sac or enclosed cavity in the body filled with liquid or partially solid material. Also refers to a protective, walled-off capsule in which an organism lies dormant.
Emmenagogue—A type of medication that brings on or increases a woman's menstrual flow.
Female athlete triad—A combination of disorders frequently found in female athletes that includes disordered eating, osteoporosis, and oligo- or amenorrhea. The triad was first officially named in 1993.
Osteoporosis—Literally meaning "porous bones," this condition occurs when bones lose an excessive amount of their protein and mineral content, particularly calcium. Over time, bone mass and strength are reduced leading to increased risk of fractures.
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