Introduction 

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

PCOS affects millions of women in the UK.

The three main features of the condition are:

  • cysts that develop in your ovaries (polycystic ovaries)
  • your ovaries do not regularly release eggs (ovulate)
  • having high levels of "male hormones" called androgens in your body

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

Read more about diagnosing polycystic ovary syndrome.

What are polycystic ovaries?

Polycystic ovaries contain a large number of harmless cysts up to 8mm in size. The cysts are under-developed sacs in which eggs develop. Often in PCOS, these sacs are unable to release an egg, meaning ovulation doesn't take place.

It's estimated that about 1 in every 5 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:

  • irregular periods or no periods at all
  • difficulty getting pregnant (because of irregular ovulation or failure to ovulate)
  • excessive hair growth (hirsutism) - usually on the face, chest, back or buttocks
  • weight gain
  • thinning hair and hair loss from the head
  • oily skin or acne  

Polycystic ovary syndrome is associated with an increased risk of problems in later life, such as type 2 diabetes and high cholesterol levels.

You should speak to your GP if you think you may have PCOS.

Read more about the symptoms of polycystic ovary syndrome.

Why it happens

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 having high levels of insulin.

Insulin is a hormone that controls sugar levels in the body. Many women with PCOS have too much insulin in their body, which 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 polycystic ovary syndrome.

Treating polycystic ovary syndrome

There's no cure for PCOS, but the symptoms can be treated. 

If you have PCOS and are overweight, losing weight and eating a healthy diet can help reduce some symptoms.

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 polycystic ovary syndrome.

A scan showing polycystic ovary syndrome 

Page last reviewed: 03/07/2013

Next review due: 03/07/2015