What is polycystic ovary syndrome?

Information for the public

Polycystic ovary syndrome (or PCOS for short) is a condition that affects how a woman's ovaries work. To understand how metformin might help in PCOS, it is necessary to understand a little about the role some hormones play in the condition.

Many, but not all, women with PCOS also have what is known as 'insulin resistance'. This is when the cells in their body do not respond as well as normal to insulin (the hormone the body produces that controls blood sugar levels). Insulin resistance in turn leads to a person having levels of insulin in their body that are higher than normal. These high levels of insulin can cause the normal balance of male and female hormones to be disturbed. More male hormones are produced leading to some of the symptoms of PCOS, such as excessive body hair (known as hirsutism), acne, period problems and problems getting pregnant. Higher levels of insulin can also cause people to gain weight; many women with PCOS are overweight or obese. These hormonal changes also mean that women with PCOS have a higher risk of developing type 2 diabetes (especially if they are also obese) and endometrial cancer (cancer in the lining of the womb).

For women with PCOS who are not trying to get pregnant, a drug called co-cyprindiol is licensed in the UK to treat severe acne that has not improved after the long-term use of oral antibiotics and excessive hair growth (although not specifically in PCOS). Brand names for co-cyprindiol include Acnocin, Cicafem, Clairette and Dianette. Co-cyprindiol contains a drug called cyproterone, which blocks the effects of male hormones on the skin. Co-cyprindiol also acts as an oral contraceptive and regulates a woman's menstrual periods. Oral contraceptive pills, which don't contain cyproterone, can also be used to regulate periods, but this use is 'off-label' (see licensing medicines for more information). Other treatment options, such as losing weight, and other treatments for acne, may be appropriate for individual women and they should discuss these with their doctor.

There is more information about polycystic ovary syndrome on NHS Choices.