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Amenorrhea

Amenorrhea may be associated with infertility, endometrial hyperplasia, or osteopenia. It may be the presenting sign of an underlying metabolic, endocrine, congenital, or gynecologic disorder.

Pathophysiology of Amenorrhea

Amenorrhea may be caused by failure of the hypothalamic-pituitary-gonadal axis, by absence of end organs, or by obstruction of the outflow tract.

Menses usually occur at intervals of 28 (±3) days, with a normal range of 18-40 days.

Amenorrhea is defined as the absence of menstruation for 3 or more months in a women with past menses (secondary amenorrhea) or the absence of menarche by age 16 in girls who have never menstruated.

Pregnancy is the most common cause of amenorrhea.

Clinical Evaluation of Amenorrhea

History

Menstrual history should include the age of menarche, last menstrual period, and previous menstrual pattern. Diet, medications, and psychologic stress should be assessed.

Galactorrhea, previous radiation therapy, chemotherapy, or recent weight gain or loss may provide important clues.

Prolonged, intense exercise, often associated with dieting, can lead to amenorrhea.

Symptoms of decreased estrogen include hot flushes and night sweats.