Polycystic Ovary Syndrome (PCOS)

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Ricardo Azziz, MD, MPH
David Ehrmann, MD

Additional Resources
PCOS Challenge
Mayo Clinic

What is polycystic ovary syndrome?

Polycystic ovary syndrome(PCOS) is a hormonal disorder defined by a group of signs and symptoms. These may include:

  • Irregular or absent menstrual periods
  • Infertility
  • Weight gain (especially at the waist)
  • Acne
  • Excess hair on the face and body
  • Thinning hair on the scalp

Women with PCOS often have many small painless cysts in the ovaries (hence the name “polycystic”). These cysts are not cancerous.

PCOS affects 7–10% of women of childbearing age and is the most common cause of infertility. In the United States, an estimated 5 to 6 million women have PCOS. PCOS is the most common hormonal disorder among women of reproductive age, but many women don’t know they have it.

PCOS affects more than reproduction. It’s also a metabolic problem that affects several body systems.

What health conditions can occur along with PCOS?

Some conditions related to PCOS are potentially serious. Many women with PCOS have decreased sensitivity to insulin, the hormone that regulates glucose (sugar) in the blood. This condition, known as insulin resistance, is a major risk factor for type 2 diabetes. Women with PCOS often have type 2 diabetes, low levels of good cholesterol (HDL), and high levels of bad cholesterol (LDL) and other blood fats, including triglycerides. These factors may increase the risk of heart attack or stroke later in life.

Women with PCOS who are overweight or obese can also develop a condition called obstructive sleep apnea, when breathing stops repeatedly during sleep. This condition can worsen the insulin resistance and cardiovascular problems of women with PCOS.

Because of irregular menstrual cycles and lack of ovulation, the lining of the uterus may not shed as often as it should. Left untreated, this may increase the risk of cancer of the uterine lining (endometrium).

What causes PCOS?

The exact cause of PCOS is unknown. In fact, there is probably more than one cause. In general, an imbalance of hormones underlies the condition. It has also been called “ovarian androgen excess” because the ovaries produce male hormones (androgens) in increased amounts.

PCOS seems to be inherited. Female relatives or children of patients with PCOS are at increased risk for having PCOS.

How is PCOS diagnosed?

Along with irregular periods, the first signs of PCOS may be the growth of facial and body hair, thinning scalp hair, acne, and weight gain. Weight gain, however, is not always present. Normal-weight women can also have PCOS.

In addition to assessing signs and symptoms of PCOS, doctors take a medical history, perform a physical exam, and check blood hormone levels. They may also perform an ovarian ultrasound and measure glucose levels in the blood.

How is PCOS treated?

While PCOS is not curable, symptoms are treatable with medications and changes in diet and exercise. Hormonal imbalances can be treated with birth control pills or anti-androgen medications. Medications that help the body respond better to insulin may also be helpful. For women whose infertility problems are not resolved with lifestyle changes alone, medications that improve ovulation (fertility drugs) may be helpful.

Questions to ask your doctor

  • Do I have PCOS?
  • What are my treatment options?
  • What are the advantages and disadvantages of each of my treatment options?
  • Am I likely to be infertile after treatment, or will I still be able to get pregnant?
  • Should I see an endocrinologist for my condition?