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When your period doesn’t come: Exploring the reasons for amenorrhea
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When a woman’s period fails to arrive, the wondering begins. The first question she may ask herself is, “Could I be pregnant?” But once that possibility has been ruled out—and she fails to menstruate for three months in a row—it’s time to look for an explanation.

Two types

Amenorrhea, or the absence of menstruation in a premenopausal woman, is classified as either primary or secondary. In primary amenorrhea, a girl reaches age 16 without having yet experienced menstruation. Most often, this is due to delayed puberty. But sometimes a genetic defect, an anatomical abnormality or another medical condition may be the cause.

In secondary amenorrhea, menstrual periods that at one time were normal become irregular or absent.

Uncovering the cause

If you have skipped several periods, alert your physician. He or she will perform a pelvic exam and look for underlying disorders that could explain the problem, such as pituitary gland disorders or polycystic ovary syndrome. He or she will try to determine if any medications you may be taking are at fault and test for hormonal imbalances. Addressing any underlying conditions, if found, can prompt normal menstruation to resume.

Other common reasons for secondary amenorrhea include:

  • Anorexia and bulimia. When a woman reaches a body weight that is too low to sustain a healthy pregnancy, the body may, in effect, shut down the reproductive system, ceasing ovulation and menstruation. This physiological mechanism may have evolved in prehistoric times to prevent pregnancy when food was scarce and babies were unlikely to survive.
  • Strenuous physical activity. Many gymnasts, ballet dancers, runners and other young female athletes experience irregular periods or amenorrhea. Experts believe this is caused by a drop in the ratio of fat to lean tissue, which affects estrogen production.
  • Obesity. Fat cells increase the amount of estrogen in a woman’s body, which can interfere with ovulation.
  • High stress levels. Unmanaged stress can affect the hypothalamus, a gland that secretes hormones which help regulate the reproductive cycle, among other bodily processes.

Although amenorrhea rarely is serious, it can put a woman at risk for osteoporosis by preventing normal estrogen production. For that reason, estrogen and calcium supplements may be recommended to protect a woman’s bone health if no underlying reason for amenorrhea is discovered. For women who hope to conceive, ovulation-stimulating medications can help. If you are concerned about missed periods, discuss the issue with your doctor.