There are certain situations that bring about menopause earlier than usual. About one percent of women cease menstruating before age 40. This is called premature menopause or premature ovarian failure. The reasons for it are largely unknown. In some cases, severe infections or tumors in the reproductive tract damage the ovaries and precipitate menopause. Other possible causes are exposure to radiation, chemotherapy drugs, and surgery that impairs blood flow to the ovaries.
When a woman has her ovaries surgically removed or rendered nonfunctional through radiation therapy, induced or artificial menopause occurs. Because this results in an abrupt and almost total loss of estrogen in the body, symptoms of induced menopause can be particularly severe. The condition is usually a side effect of treatment for abdominal disease, such as ovarian cancer. Elective removal of the ovaries is sometimes used to prevent ovarian cancer particularly where there is a family history of the disease. The practice is highly controversial in premenopausal women, though less so in postmenopausal women. In the past, it was also common to remove the ovaries during a hysterectomy (surgical removal of the uterus), but today in premenopausal women the ovaries are left in place whenever possible.