An ovarian cyst is a fluid-filled sac that develops on a woman’s ovary. They are very common and do not usually cause any symptoms.

Most ovarian cysts occur as part of the normal workings of the ovaries. These cysts are generally harmless and disappear without treatment in a few months.

Signs and symptoms

An ovarian cyst will usually only cause symptoms if it splits (ruptures), is very large, or it blocks the blood supply to the ovaries. In these cases, you may have:

  • pelvic pain – this can range from a dull, heavy sensation to a sudden, severe and sharp pain
  • pain during sex
  • difficulty emptying your bowels
  • a frequent need to urinate
  • heavy periods, irregular periods or lighter periods than normal
  • bloating and a swollen tummy
  • feeling very full after only eating a little
  • difficulty getting pregnant (although fertility is unaffected in most women with ovarian cysts – see below)

Visit your GP if you have persistent symptoms of an ovarian cyst.

Immediately contact your GP, local out-of-hours service or NHS 111 – or go to your nearest accident and emergency (A&E) department – if you have sudden, severe pelvic pain.

The ovaries

The ovaries are two small, bean-shaped organs that are part of the female reproductive system. A woman has two ovaries – one each side of the womb (uterus).

The ovaries have two main functions. They are:

  • to release an egg approximately every 28 days as part of the menstrual cycle
  • to release the female sex hormones, oestrogen and progesterone, which play an important role in female reproduction

Ovarian cysts may affect both ovaries at the same time, or they may only affect one.

Types of ovarian cyst

The two main types of ovarian are:

  • functional ovarian cysts – cysts that develop as part of the menstrual cycle and are usually harmless and short-lived; these are the most common type of ovarian cyst
  • pathological ovarian cysts – cysts that occur due to abnormal cell growth; these are much less common

Ovarian cysts can sometimes also be caused by an underlying condition, such as endometriosis.

The vast majority of ovarian cysts are non-cancerous (benign), although a small number are cancerous (malignant). Cancerous cysts are more common in women who have been through the menopause.

Read more about the causes of ovarian cysts.

Diagnosing ovarian cysts

If your GP thinks you may have an ovarian cyst, you'll probably be referred for an ultrasound scan, carried out by using a probe placed inside your vagina.

If a cyst is identified during the ultrasound scan, you may need to have this monitored with a repeat ultrasound scan in a few weeks, or your GP may refer you to a gynaecologist (a doctor who specialises in female reproductive health).

If there is any concern that your cyst could be cancerous, your doctor will also arrange blood tests to look for high levels of chemicals that can indicate ovarian cancer.

However, having high levels of these chemicals doesn't necessarily mean you have cancer, as high levels can also be caused by non-cancerous conditions such as endometriosis, a pelvic infection, fibroids or even being on your period.

How ovarian cysts are treated

Whether an ovarian cyst needs to be treated will depend on:

  • its size and appearance
  • whether you have any symptoms
  • whether you have been through the menopause

In most cases, the cyst often disappears after a few months. A follow-up ultrasound scan may be used to confirm this.

Due to the slightly increased risk of ovarian cancer in post-menopausal women, regular ultrasound scans and blood tests are usually recommended over the course of a year to monitor the cyst.

Large cysts, those causing symptoms, and those that could be cancerous, may need to be surgically removed.

Read more about treating ovarian cysts.

Do ovarian cysts affect fertility?

Ovarian cysts don't usually prevent you from getting pregnant, although they can sometimes make it harder to conceive.

If you need an operation to remove your cysts, your surgeon will aim to preserve your fertility whenever possible. This may mean removing just the cyst and leaving the ovaries intact, or only removing one ovary.

In some cases, surgery to remove both your ovaries may be necessary, in which case you will no longer produce any eggs. Make sure you talk to your surgeon about the potential effects on your fertility before your operation.

Page last reviewed: 09/12/2014

Next review due: 09/12/2016