Oligomenorrhea

Definition: Bleeding intervals longer than 35 days. Oligomenorrhea may be transient during the transition to a normal cycle. Evaluation of the physical status, sexual development, and the bleeding pattern is sufficient in this setting.

But oligomenorrhea may indicate a relevant endocrine disturbance with possible consequences for future life and health. Exploration is indicated if there are signs or symptoms of an endocrinopathy or organic manifestations. If not, a work-up should be initiated if oligomenorrhea persists for longer than 2 years.

In addition, factors such as late menarche and a prolonged interval between beginning of sexual development and menarche are indications for diagnostic evaluation.

Endocrine exploration consists of a basic hormone panel. Levels of FSH, LH, Prl, E2, T and DHEA-S are sufficient to assess the endocrine situation.

If they are all within a physiological range during development, expectant follow-up and reassurance are sufficient. Abnormal levels should be identified and their relevance assessed. Disturbances within the hypothalamus-pituitaryovarian axis as well as hyperprolactinemia and hyperandrogenemia may be detected. These abnormalities are true endocrinopathies (table 4) and require treatment.

Hypothalamic origin: A variety of physical and psychological stresses can cause oligomenorrhea, particularly during development of the cycle. Stresses can affect the pulsatile secretion pattern of GnRH and, consequently, gonadotropin secretion. Low levels of FSH and LH and relatively low levels of estradiol are characteristic. Low body weight, eating disorders, and heavy exercise and sports are relatively common reasons.

Treatment should be initiated if oligomenorrhea persists over a prolonged period or if the long bleeding interval is disturbing. If estradiol secretion is sufficient, progestins in the second part of the cycle are an option to induce secretory conversion of the endometrium and a regular bleeding pattern. Also this prevents permanent proliferation under the influence of estradiol and thus protects against endometrial hyperplasia and carcinoma.

If estradiol secretion is low, an estrogen-progestogen combination is necessary, either as a biphasic combination of natural hormones as in early postmenopause or as a contraceptive pill. The result is a regular bleeding pattern and the correction of an estrogen deficit. Also, bone mass is preserved and osteoporosis prevented.

Pituitary origin: From a functional situation, oligomenorrhea of pituitary origin is similar to the hypothalamic form. The management is the same. Low levels of gonadotropins and estradiol are characteristic. Secondary oligomenorrhea may be a sign of an organic lesion such as a brain tumor.

The work-up should include evaluation for pituitary tumors and beginning hydrocephalus.