What is polycystic ovary syndrome (PCOS)?

Polycystic ovary syndrome (say "pah-lee-SIS-tik OH-vuh-ree SIN-drohm") is a problem in which a woman’s hormones are out of balance. It can cause upsetting changes in the way you look and problems with your periods. If it is not treated, over time it can lead to serious health problems, such as diabetes and heart disease.

Polycystic ovary syndrome (or PCOS) affects up to 1 in 10 women, and often the symptoms begin in the teen years. Treatment can help control the symptoms and prevent long-term problems.

What are hormones, and what happens in PCOS?

Hormones are chemical messengers that trigger many different processes, including growth and energy production. Often the job of one hormone is to signal the release of another hormone.

For reasons that are not well understood, in PCOS the hormones get out of balance. One hormone change triggers another, which changes another. This makes a vicious circle of out-of-balance hormones. For example:

• The sex hormones get out of balance. Normally, the ovaries make a tiny amount of male sex hormones (androgens). In PCOS, they start making more androgens. This may cause you to stop ovulating, get acne, gain weight, and grow extra facial and body hair.
• The body may have a problem using insulin, called insulin resistance. When the body doesn't use insulin well, blood sugar levels go up. Over time, this increases your chance of getting diabetes.

What are the symptoms?

Symptoms tend to be mild at first. You may have only a few symptoms or a lot of them. The most common symptoms are:

• Acne.
• Weight gain and trouble losing weight.
• Extra hair on the face and body. Often women get thicker and darker facial hair and more hair on the chest, belly, and back.
• Thinning hair on the scalp.
• Irregular periods. Often women with PCOS have fewer than 9 periods a year. Some women have no periods. Others have very heavy bleeding.
• Fertility problems. Many women with PCOS have trouble getting pregnant (infertility).

Some women with PCOS grow many small cysts on their ovaries. That is why it is called polycystic ovary syndrome. But this doesn't always happen, and the cysts are not harmful.

What causes PCOS?

The symptoms of PCOS are caused by changes in hormone levels. But experts are not sure what causes the hormone changes.

PCOS seems to run in families, so your chance of having it is higher if other women in your family have it.

How is PCOS diagnosed?

To diagnose PCOS, the doctor will:

• Ask questions about your past health, symptoms, and menstrual cycles.
• Do a physical exam to look for signs of PCOS, such as extra body hair and high blood pressure. The doctor will also check your height and weight to see if you have a healthy body mass index (BMI).
• Do a number of lab tests to check your blood sugar, insulin, and other hormone levels. Hormone tests can help rule out thyroid or other gland problems that could cause similar symptoms.