SIGNS AND SYMPTOMS — The changes in hormone levels, described above, cause the classic symptoms of PCOS, including absent or irregular menstrual periods, abnormal hair growth or loss, acne, weight gain, and difficulty becoming pregnant.

Signs and symptoms of PCOS usually begin around the time of puberty, although some women do not develop symptoms until adulthood. Because hormonal changes vary from one woman to another, patients with PCOS may have mild to severe acne, facial hair growth, or scalp hair loss.

Menstrual irregularity — If ovulation does not occur, the lining of the uterus (called the endometrium) does not uniformly shed and regrow as in a normal menstrual cycle. Instead, the endometrium becomes thicker and may shed irregularly, which can result in heavy and/or prolonged bleeding. Irregular or absent menstrual periods can increase a woman's risk of endometrial overgrowth (called endometrial hyperplasia) or even endometrial cancer.

Women with PCOS usually have fewer than six to eight menstrual periods per year. Some women have normal cycles during puberty, which may become irregular if the woman becomes overweight.

Weight gain and obesity — PCOS is associated with gradual weight gain and obesity in about one-half of women. For some women with PCOS, obesity develops at the time of puberty.

Hair growth and acne — Male-pattern hair growth (hirsutism) may be seen on the chin, neck, sideburn area, chest, and upper abdomen. Acne is a skin condition that causes oily skin and blockages in hair follicles, leading to pimples.

Insulin abnormalities — PCOS is associated with elevated levels of insulin in the blood. Insulin is a hormone that is produced by specialized cells within the pancreas; insulin regulates blood glucose levels. When blood glucose levels rise (after eating, for example), these cells produce insulin to help the body use glucose for energy.

• If glucose levels do not respond to normal levels of insulin, the pancreas produces more insulin. Excess production of insulin is called hyperinsulinemia.

• When increased levels of insulin are required to maintain normal glucose levels, a person is said to be insulin resistant.

• When the blood glucose levels are not completely controlled, even with increased amounts of insulin, the person is said to have impaired glucose tolerance.

• If blood glucose levels continue to rise despite increased insulin levels, the person is said to have type 2 diabetes.

These conditions are diagnosed with blood tests.

Insulin resistance and hyperinsulinemia can occur in both normal-weight and overweight women with PCOS. Among women with PCOS, up to 35 percent of obese women develop impaired glucose tolerance by age 40, while up to 10 percent of obese women develop type 2 diabetes. The risk of these conditions is much higher in women with PCOS compared to women without PCOS.

Infertility — Many women with PCOS do not ovulate regularly, and it may take these women longer to become pregnant. An infertility evaluation is often recommended after 6 to 12 months of trying to become pregnant. (See "Treatment of infertility" below).

Heart disease — Women who are obese and who also have insulin resistance or diabetes have an increased risk of coronary artery disease, the narrowing of the arteries that supply blood to the heart. Both weight loss and treatment of insulin abnormalities can decrease this risk. Other treatments (eg, cholesterol lowering medications, treatments for high blood pressure) may also be recommended.

Sleep apnea — Sleep apnea is a condition that causes brief spells where breathing stops (apnea) during sleep. Patients with this problem often experience fatigue and daytime sleepiness. In addition, there is evidence that people with untreated sleep apnea have an increased risk of cardiovascular problems such as high blood pressure, heart attack, abnormal heart rhythms, or stroke. This risk may be changes in heart rate and blood pressure that occur during sleep.

Sleep apnea may occur in up to 30 percent of women with PCOS. The condition can be diagnosed with a sleep study, and several treatments are available.