Polycystic ovary syndrome (PCOS) is a condition that affects how a woman’s ovaries work.

It's difficult to know exactly how many women have PCOS, but it's thought to be very common and affect millions of women in the UK.

The three main features of PCOS are:

  • cysts that develop in your ovaries (polycystic ovaries)
  • your ovaries not regularly releasing eggs (ovulating)
  • high levels of "male hormones" called androgens in your body

You'll usually be diagnosed with PCOS if you have at least two of these features.

Read more about diagnosing PCOS.

Polycystic ovaries

Polycystic ovaries contain a large number of harmless cysts up to 8mm (approximately 0.3in) in size. The cysts are under-developed sacs in which eggs develop. In PCOS, these sacs are often unable to release an egg, which means that ovulation doesn't take place.

It's estimated that about one in every five women in the UK has polycystic ovaries, but more than half of these have no symptoms.

Signs and symptoms

Symptoms of PCOS usually become apparent during your late teens or early twenties. They can include:

PCOS is also associated with an increased risk of developing health problems in later life, such as type 2 diabetes and high cholesterol levels.

Read more about the symptoms of PCOS.

What causes PCOS?

The exact cause of PCOS is unknown, but it often runs in families.

The condition is associated with abnormal hormone levels in the body, including high levels of insulin.

Insulin is a hormone that controls sugar levels in the body. Many women with PCOS are resistant to the action of insulin in their body and so produce higher levels of insulin to overcome this. This contributes to the increased production and activity of hormones such as testosterone. Being overweight increases the amount of insulin your body produces.

Read more about the causes of PCOS.

Treating PCOS

There's no cure for PCOS, but the symptoms can be treated. Speak to your GP if you think you may have the condition.

If you have PCOS and you're overweight, losing weight and eating a healthy, balanced diet can make some symptoms better.

Medications are also available to treat symptoms such as excessive hair growth, irregular periods and fertility problems.

If fertility medications are ineffective, a simple surgical procedure called laparoscopic ovarian drilling (LOD) may be recommended. This involves using heat or a laser to destroy the tissue in the ovaries that's producing androgens, such as testosterone.

With treatment, most women with PCOS are able to get pregnant.

Read more about treating PCOS.

Page last reviewed: 13/05/2015

Next review due: 13/05/2017