I have a friend who has missed her period for four months and she is not pregnant. She won't see a doctor! What can be causing this? How serious could this be?

--Andrew

The obvious first question is why won't she see a doctor? We don't bite! That should be step number one.

As for causes of amenorrhea (lack of menstrual periods), there are many. Pregnancy is the most common. Another is stress. Being significantly overweight or underweight can also upset the delicate hormone balance that is necessary for regular menstrual cycles. An underactive thyroid can also upset this balance and cause periods to disappear. Premature failure of the ovaries (early menopause) is a possibility. (You didn't tell me how old your friend is, but I'm assuming she's under 40.)

There are consequences to amenorrhea, depending on the underlying cause. If amenorrhea is caused by lack of ovulation (and there are many reasons for this), then a chronically higher-than-usual level of estrogen, without the normal high progesterone level that comes with the latter part of the cycle, can increase the risk of cancer of the uterine lining. This can also occur with obesity (which can also increase the risk of diabetes, high blood pressure and heart disease). If estrogen levels are abnormally low, then osteoporosis can occur. An underactive thyroid gland, left untreated, not only can cause annoying symptoms like fatigue, cold intolerance and constipation, but also increases the risk of developing high blood pressure, anemia, cognitive (mental functioning) difficulties, nerve damage and heart problems.

The bottom line: Your friend needs to see her gynecologist or family doctor.