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Polycystic ovary syndrome (PCOS)

Polycystic ovary syndrome, or PCOS, is a complex hormonal condition, affecting up to around 1 in every 10 women.

How is PCOS diagnosed?

The diagnosis of PCOS can be made if a woman has any two of the following three features (provided other conditions are ruled out):

  • Infrequent or absent ovulation.
  • Clinical and/or biochemical signs of androgen excess. The clinical signs are oily skin, acne, excessive hair growth on face, chest, abdomen or thighs, and thinning of hair on the crown of the head. Doctors can also request blood tests to look for a biochemical suggestion of androgen excess and to rule out other conditions.
  • Polycystic ovaries detected on an ultrasound scan.

Androgens are sometimes called male hormones. Men have high levels of androgens, which are responsible for male body changes such as hair growth and muscle mass. In women, androgens are necessary to make oestrogen. Women with PCOS may have features of androgen excess.

Many women with PCOS are resistant to the action of the hormone insulin. This means that it takes larger than normal amounts of insulin to maintain normal blood sugar levels. These women have an increased risk of diabetes. High insulin levels caused by insulin resistance can lead to excessive androgen production.

What causes PCOS?

The causes of PCOS are not completely understood. It is likely that a genetic tendency - heredity - is involved.

What are the signs and symptoms of PCOS?

Women with PCOS can have a wide spectrum of signs and symptoms, from very mild to severe. They may include:

  • Infrequent or absent menstrual periods (as a result of infrequent or absent ovulation)
  • Signs of androgen excess, including oily skin and acne, excessive hair growth (on the face, chest, abdomen or thighs), thinning of hair on the crown of the head
  • Obesity
  • Subfertility or infertility - as a result of infrequent or absent ovulation
  • Heavy vaginal bleeding - although infrequent or absent periods are more common, occasionally women may experience heavy bleeding
  • Acanthosis nigricans - darkening and thickening of certain areas of the skin, especially in skin folds
  • Increased risk of type 2 diabetes
  • Increased risk of high cholesterol
  • Increased risk of metabolic syndrome - both PCOS and metabolic syndrome are associated with insulin resistance
  • Increased risk of obstructive sleep apnoea
  • There remains uncertainty among doctors as to whether women with PCOS have an increased risk of developing cancer of the lining of the uterus (endometrial cancer). More research is needed.
  • Increased risk of diabetes in pregnancy, or gestational diabetes.

How is PCOS treated?

There is no cure for PCOS. Treatment depends on the particular patient's signs and symptoms, as well as her goals. Treatment options include:

  • For women who are not ready to become pregnant, oral contraceptive pills can be an excellent way to replace progesterone, establish regular withdrawal bleeds and reduce androgen levels.
  • If a woman wants to become pregnant, treatment is aimed at establishing regular ovulation.
  • For women with PCOS and resistance to insulin, medication to improve sensitivity to insulin may be useful.
  • For all women, lifestyle advice should be offered, including healthy eating, exercise and weight loss, if women are overweight.
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