Polycystic ovary syndrome (PCOS) is a condition in which there is an imbalance in a woman’s hormones. Normally, the ovaries and adrenal glands make a small amount of male sex hormones called androgens, which help the reproductive system function properly. But in a woman with PCOS, the ovaries, adrenal glands, or both overproduce androgens. This can lead to excessive facial and body hair, hair loss, acne, and obesity, among other symptoms.
High levels of androgens also interfere with the development of ovarian follicles, which produce the hormones estrogen and progesterone and release an egg when a woman ovulates. As a result, a woman may develop multiple follicles that don’t mature, also known as cysts. This is called polycystic ovaries.
However, some women with the condition never develop cysts. And, having ovarian cysts doesn’t mean you have PCOS.
Women with PCOS may also experience insulin resistance, in which the body doesn’t effectively use insulin, a hormone that regulates blood sugar. As a result, blood sugar levels may rise. Left untreated, this can lead to type 2 diabetes.
The severity of PCOS symptoms can vary. Some women have a mild form of the condition and may not know they have it, while others have severe symptoms that affect their quality of life and fertility. The symptoms tend to improve after menopause, when the ovaries stop functioning and androgen levels drop. Still, compared to other postmenopausal women, those with PCOS have higher androgen levels and insulin resistance.
PCOS is a syndrome, not a disease. In many women, insulin resistance may trigger excess androgen production. It is not fully understood what causes PCOS, but doctors believe that genes and environmental factors may play a role.
The condition typically begins around puberty, although the symptoms may not appear until early adulthood. Some women discover they have the condition after they have trouble getting pregnant and doctors perform a series of tests.
Women who are not treated for PCOS may be at risk for developing conditions that increase the risk of cardiovascular disease, including high blood pressure, obesity, gestational diabetes, and high cholesterol.
Women with the condition are also at risk of developing increased thickness of the uterine lining, called endometrial hyperplasia; uterine cancer; and having a preterm delivery and preeclampsia, in which a woman experiences high blood pressure during pregnancy. They also have a greater chance of having a miscarriage.
To receive a diagnosis of PCOS, you must meet two of the following criteria:
To diagnose PCOS, an endocrinologist, a doctor who specializes in hormonal disorders, conducts a physical exam. He or she checks you for increased body and facial hair, thinning scalp hair, acne, and other symptoms of increased androgen levels. The doctor also asks about your medical history, including the regularity of your menstrual cycle.
He or she may also order the following tests:
Your doctor may check your blood for levels of androgens, including testosterone, which tends to be higher in women with PCOS. He or she may also test your insulin levels, which are usually elevated in women with the condition.
The doctor may also measure levels of the hormones involved in ovulation, such as luteinizing hormone (LH), follicle-stimulating hormone (FSH), and progesterone. These tests can indicate whether you are ovulating.
Your doctor may also test your blood to rule out conditions that mimic PCOS, as well as tumors of the ovaries or adrenal glands. He or she may also check your blood for signs of hypothyroidism, in which the thyroid gland doesn’t produce enough thyroid hormone, leading to fatigue and possibly depression. A blood test can also reveal whether you have high cholesterol and high blood sugar.
Your doctor may recommend a pelvic ultrasound—a test that uses sound waves to create images of the uterus and the ovaries on a computer monitor—to look for ovarian cysts. However, this test might not show ovarian cysts in women with PCOS who are taking birth control pills.
Learn more about our research and professional education opportunities.