Missing or absent menstrual periods, when not due to pregnancy, usually have a hormonal cause. One common cause amongst young women is polycystic ovarian syndrome (PCOS). This is a hormonal disorder in which a woman’s body produces abnormally high levels of the male hormone, called androgens. These high levels of androgens prevent the ovaries from producing enough progesterone, which is necessary for a normal menstrual cycle. This results in undeveloped egg follicles, which turn into small cysts in the ovaries that prevent ovulation.
Another common cause of missing menstrual periods especially amongst older women is menopause, in which a woman stops having periods because her ovaries are no longer producing estrogen. Other reasons for absent menstrual periods include lack of ovulation due to causes other than PCOS, excess prolactin secretion by the brain, thyroid disorders, eating disorders and excessive exercise. Rarely, absent menstrual periods can be caused by scarring of the uterine cavity as a result of a medical curettage procedure.
The reason for absent or infrequent menstrual periods usually can be determined by the combination of a medical history, physical examination, gynaecological ultrasound scan and blood tests.
Treatment options depend on the cause of the infrequent or absent menstrual periods. Treatment can involve lifestyle changes such as moderation of diet or exercise habits and hormonal medication such as oral contraceptive pills, thyroid medication or estrogen replacement therapy.