Causes. Hyperplasia generally occurs when your body doesn't produce enough progesterone to rein in the effects of estrogen, which spurs cells of the uterine lining (endometrium) to divide. Hyperplasia is most common during adolescence and as a woman approaches menopause. Women with polycystic ovary syndrome and those on estrogen therapy (without progesterone) also have an elevated risk of endometrial hyperplasia. Obesity and late menopause (after age 55) are other known risk factors.

Symptoms. Bleeding between normal menstrual periods, heavy menstrual flow (saturating a tampon or pad once every hour), bleeding after menopause and vaginal discharge (especially after menopause) are possible signs of hyperplasia.

Diagnosis. The disorder is usually diagnosed by examining a sample of the endometrium obtained during an endometrial biopsy, a D&C or a hysteroscopy.

Treatment. Hyperplasia without atypia may need no treatment since it often disappears on its own. However, treatment with progesterone to reverse the hyperplasia is often suggested.

Because hyperplasia with atypia persists in about 75 percent of cases after multiple D&Cs and progestin treatment, and up to 15 percent of women with atypia will develop endometrial cancer, hysterectomy is usually recommended. If you are planning a pregnancy, high-dose progestin may first be recommended.

Prevention. There is no known prevention for endometrial hyperplasia other than regular exposure to progesterone for at least three months.