What Is Menopause?

Menopause means that a woman has had a final menstrual period, without another occurring in the following year.

In a three- to five-year period preceding a woman’s final menstrual period, known as the perimenopause, her ovaries produce less and less estrogen and progesterone, the two major female hormones. Together with two other female hormones, known as follicle-stimulating hormone and luteinizing hormone, estrogen and progesterone orchestrate ovulation, menstruation and, if fertilization occurs, pregnancy.

During the perimenopause, menstrual periods may become irregular or unusually light or heavy. Ovulation (the monthly release of an egg) declines and stops. Until menopause has actually occurred (that is, a year has passed since the last period), a sexually active woman should still practice birth control if she wants to avoid conception, since there is at least a remote risk of becoming pregnant. Menopause also can be brought on by surgical removal of the ovaries—a procedure called an oophorectomy and induced by chemotherapy or pelvic radiation therapy. When does it happen?

Perimenopause may begin during a woman’s 40s, menopause around age 50—though the process varies from woman to woman. About half of all women stop menstruating by age 48; by age 52, 85 percent will have reached menopause. If a woman ceases to menstruate before age 40, it is classified as “premature ovarian failure.” Women who have had one ovary surgically removed don’t experience menopause any earlier than women with two ovaries. Ethnicity, marital status, genetics, and geography do not seem to influence menopause. Smokers, however, experience menopause, on average, two years earlier than nonsmokers. At menopause, estrogen levels markedly decrease but estrogen production does not completely stop: The ovaries still produce a small amount of estrogen, as do fat cells and the adrenal glands.

How does menopause affect your health?

The effects of estrogen and progesterone extend far beyond the reproductive system. A decrease in these important hormones causes both short- and long-term changes.

Before menopause, for example, few women experience coronary artery disease. But after age 50, women begin to develop the disorder at an increasing rate, so that by age 65 the risk of a heart attack is as great in women as it is in men.

The decline in estrogen production is also associated with a loss of bone mass, causing bones to become thinner and more brittle—the condition known as osteoporosis, which can lead to debilitating fractures.