It is well known that menstrual bleeding (period) occurs approximately every 28 days (± 4 days). Although some variations can normal, menstrual bleeding at intervals of greater than 35-36 days may indicate oligomenorrhea — abnormally infrequent menstrual bleeding characterized by three to six menstrual cycles per year.
In most cases oligomenorrhea starts from puberty but it may develop suddenly or it may follow a period of gradually lengthening cycles. Sometimes ologomenorrhea can progress to secondary amenorrhea.
Very often in puberty (beginning of the menstrual cycle) and after 50 (end of menstrual cycles) females can have irregular periods (oligomenorrhea). It is normal and is usually the result of misbalanced/imperfect coordination between the hypothalamus, the pituitary gland, and the ovaries (all hormones). Very rare for no apparent reason, some women menstruate (with ovulation occurring) on a regular schedule as infrequently as once every two months. For these mentioned groups of women oligomenorrhea can be considered temporary and/or normal.
As oligomenorrhea is commonly associated with anovulation, it’s common in infertile, early postmenarchal, and perimenopausal women. This sign usually reflects abnormalities of the hormones that govern normal endometrial function.
- menstrual periods at intervals of more than 35-36 days;
- unusually light menstrual flow;
- irregular menstrual periods with unpredictable flow - only 4 to 9 periods in the whole year;
- difficulty conceiving - infertility
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.
Oligomenorrhea can be a symptom of several medical conditions and main causes of oligomenorrhea include the following:
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. 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. Women with PCOS show menstrual irregularities that range from oligomenorrhea and amenorrhea to very heavy and irregular periods. PCOS affects about 6% of premenopausal women and is related to excess androgen production.
Oligomenorrhea that occurs in adolescents is often caused by immaturity or lack of synchronization between the hypothalamus, pituitary gland, and ovaries. Teenage girls may experience oligomenorrhea associated with immature hormonal function. However, prolonged oligomenorrhea or the development of amenorrhea may signal congenital adrenal hyperplasia or Turner’s syndrome.
Female Athlete Triad. Female Athlete Triad is a syndrome in which eating disorders (or low energy availability), amenorrhoea/oligomenorrhoea and decreased bone mineral density (osteoporosis and osteopenia) are present. Also known simply as the Triad, this condition is seen in females participating in sports that emphasize leanness or low body weight. The Triad is a serious illness with lifelong health consequences and can potentially be fatal.
Increased levels of androgens are very typical for adrenal hyperplasia and oligomenorrhea may occur with signs of androgen excess, such as clitoral enlargement and male distribution of hair, fat, and muscle mass.
Eating disorders like bulimia and anorexia nervosa
Oligomenorrhea can be noted in women with dramatic change of weight - more than 20% of ideal body weight. Anorexia nervosa may cause sporadic oligomenorrhea or even amenorrhea. Typically, the patient displays dramatic skeletal muscle atrophy and loss of fatty tissue; dry or sparse scalp hair; lanugo on the face and body; and blotchy or sallow, dry skin. Common are also constipation, decreased libido and sleep disturbances.
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.
Oligomenorrhea could be very early sign of diabetes mellitus. In insulin-dependent diabetes women could suffer from menstrual disturbances always. Associated findings include excessive hunger, polydipsia, polyuria, weakness, fatigue, dry mucous membranes, poor skin turgor, irritability and emotional lability, and weight loss.
It is well know that thyroids dysfunctions often provoke menstrual dysfunctions. Besides oligomenorrhea, hypothyroidism may result in fatigue; forgetfulness; cold intolerance; unexplained weight gain; constipation; bradycardia; decreased mental acuity; dry, flaky, inelastic skin; puffy face, hands, and feet; hoarseness; periorbital edema; ptosis; dry, sparse hair; and thick, brittle nails.
Hyperthyroidism is the term for overactive tissue within the thyroid gland causing an overproduction of thyroid hormones which is always provoking problems in menstrual cycle. Thyrotoxicosis could produce oligomenorrhea along with reduced fertility. Cardinal findings include irritability, weight loss despite increased appetite, dyspnea, tachycardia, palpitations, diarrhea, tremors, diaphoresis, heat intolerance, an enlarged thyroid and, possibly, exophthalmos.
Hyperprolactinemia - Prolactin-secreting pituitary tumor
Oligomenorrhea and/or amenorrhea could be the first signal of hyperprolactinemia (prolactin-secreting pituitary tumor). Accompanying findings include galactorrhea, infertility, loss of libido and sparse pubic hair. A headache and visual field disturbances such as diminished peripheral vision, blurred vision, diplopia, and hemianopia could be a sign for tumor expansion.
Menstrual cycle can be disturbed also because of stress - emotional or physical stress. In both cases hormonal dysfunctions are noted. Changes in female hormones can be a reason for oligomenorrhea.
Drugs that increase androgen levels — such as corticosteroids, corticotropin, anabolic steroids, danocrine, injectable and implanted hormonal contraceptives — could cause oligomenorrhea. Oligomenorrhea can be temporary and normal periods can be resumed after stopping of mentioned drugs. Other drugs that may cause oligomenorrhea include phenothiazine derivatives and amphetamines, and antihypertensive drugs, which increase prolactin levels.
The level of female hormones is usually changed during whole reproductive period. During perimenopause female hormones are naturally decreased which is developing oligomenorrhea and following amenorrhea - usually it indicates the impending onset of menopause.
The main reason of oligomenorrhea during chronic illnesses is disturbed interactions between hypothalamus, pituitary gland and ovaries.
Women suffering from oligomenorrhea could develop the following complications:
- Cardiovascular diseases,
- Uterine cancer.
As oligomenorrhea can be a symptom of several health conditions and diseases, the treatment should be done according to the main cause of oligomenorrhea.
Puberty and Pre-menopause. Menopausal women and teenagers usually do not require any treatment.
Increased physical activities. Athletes suffering from oligomenorrhea (due to intense training and steroids) are recommended to have a balanced diet rich in nutrients.
Birth control pills. Pills are well known as a method for regulating menstrual dysfunctions. Birth control pills are also prescribed to correct the hormonal imbalance during oligomenorrhea.
PCOS. Treatments during PCOS mainly include hormonal drugs or injections which could regulate menstrual cycle and stimulate normal ovulation.
Eating disorders. Oligomenorrhea developed because of eating disorder is usually treated by psychotherapy and medical treatment. If woman is overweight then she is advised to reduce weight to normal according to BMI.
Hyperprolactinemia and Tumors. If the cause of oligomenorrhea is a tumor then it could be treated by bromocroptine or tumor could be surgically removed.
OLIGOMENORRHEA risk groups
Women with Female Athlete Triad.
Professional ballet dancers, sportsmen/gymnasts, and ice skaters;
Models and weight addicted teenagers;
Women with hormonal dysfunctions;
Stressful professions or stressful life;
Women with chronic diseases;
Women using drugs.
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.