Introduction

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 service – 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 cylce
  • 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

Causes

Ovarian cysts often develop for no apparent reason in women who have monthly periods.

They can also affect women who no longer have periods, because they have been through the menopause.

Types of ovarian cyst

There are a many different types of ovarian cyst, which can be categorised as either "functional cysts" or "pathological cysts".

Functional cysts

Functional ovarian cysts form due to a minor problem in the menstrual cycle. They affect girls and women who have not been through the menopause, and are very common.

Each month, a woman's ovaries release an egg, which travels down the fallopian tubes into the womb (uterus), where it can be fertilised by a man's sperm.

Each egg forms inside the ovary in a structure known as a follicle. The follicle contains fluid that protects the egg as it grows and it bursts when the egg is released.

However, sometimes a follicle does not release an egg, or discharge its fluid and shrink after the egg is released. If this happens, the follicle can swell and become a cyst.

Functional cysts can also develop when the tissue left behind after an egg has been released (corpus luteum) fills with fluid.

Functional cysts are non-cancerous (benign) and are usually harmless, although they can sometimes cause symptoms such as pelvic pain. Most will disappear without treatment in a few months.

Pathological cysts

Pathological cysts are cysts caused by abnormal cell growth and aren't related to the menstrual cycle. They can develop before and after the menopause.

Pathological cysts develop from either the cells used to create eggs or the cells that cover the outer part of the ovary.

They can sometimes burst or grow very large and block the blood supply to the ovaries.

Pathological cysts are usually non-cancerous, but a small number are cancerous (malignant) and they are often surgically removed.

Conditions that cause ovarian cysts

In some cases, ovarian cysts are caused by certain conditions, such as endometriosis.

Endometriosis occurs when pieces of the tissue that line the womb (endometrium) are found outside the womb in the fallopian tubes, ovaries, bladder, bowel, vagina or rectum. Blood-filled cysts can sometimes form in this tissue.

Polycystic ovary syndrome (PCOS) is a condition that causes lots of small, harmless cysts to develop on your ovaries. The cysts are small egg follicles that do not grow to ovulation and are the result of altered hormone levels.

Treatment

In most cases, ovarian cysts disappear in a few months without the need for treatment.

Whether treatment is needed will depend on:

  • its size and appearance
  • whether you have any symptoms
  • whether you have had the menopause (post-menopausal women have a slightly higher risk of ovarian cancer)

Watchful waiting

In most cases, a policy of "watchful waiting" is recommended.

This means you won't receive immediate treatment, but you may have an ultrasound scan a few weeks or months later to check if the cyst has gone.

Due to the slightly increased risk of ovarian cancer in post-menopausal women, women who have been through the menopause may be advised to have ultrasound scans and blood tests every four months for a year.

If the scans show that the cyst has disappeared, further tests and treatment are not usually necessary. If the cyst is still there, surgery may be recommended.

Surgery

Large or persistent ovarian cysts, or cysts that are causing symptoms, will usually need to be surgically removed.

Surgery will also normally be recommended if there are concerns that the cyst could be cancerous or could become cancerous.

There are two types of surgery used to remove ovarian cysts:

  • a laparoscopy
  • a laparotomy

These are usually carried out under general anaesthetic.

Laparoscopy

Most cysts can be removed using laparoscopy. This is a type of keyhole surgery where small cuts are made in your tummy and gas is blown into the pelvis to allow the surgeon to access your ovaries.

A laparoscope (a small, tube-shaped microscope with a light on the end) is passed into your abdomen so the surgeon can see your internal organs. The surgeon then removes the cyst through the small cuts in your skin.

After the cyst has been removed, the cuts will be closed using dissolvable stitches.

A laparoscopy is preferred because it causes less pain and has a quicker recovery time. Most women are able to go home on the same day or the following day.

Laparotomy

If your cyst is particularly large, or there is a chance it could be cancerous, a laparotomy may be recommended.

During a laparotomy, a single, larger cut is made in your tummy to give the surgeon better access to the cyst.

The whole cyst and ovary may be removed and sent to a laboratory to check whether it's cancerous. Stitches or staples will be used to close the incision.

You may need to stay in hospital for a few days after the procedure.

After surgery

After the ovarian cyst has been removed, you will feel pain in your tummy, although this should improve in a day or two.

Following laparoscopic surgery, you will probably need to take things easy for two weeks. Recovery after a laparotomy will usually take longer, possibly around six to eight weeks.

If the cyst is sent off for testing, the results should come back in a few weeks and your consultant will discuss with you whether you need any further treatment.

Contact your GP if you notice the following symptoms during your recovery:

  • heavy bleeding
  • severe pain or swelling in your abdomen
  • a high temperature (fever)
  • dark or smelly vaginal discharge

These symptoms may indicate an infection.

Your fertility

If you have not been through the menopause, your surgeon will try to preserve as much of your reproductive system as they can. It's often possible to just remove the cyst and leave both ovaries intact, which means your fertility should be largely unaffected.

If one of your ovaries needs to be removed, the remaining ovary will still release hormones and eggs as usual. Your fertility shouldn't be significantly affected, although you may find it slightly harder to get pregnant.

Occasionally, it may be necessary to remove both ovaries in women who have not been through the menopause. This will trigger an early menopause and mean you no longer produce any eggs.

However, it may still be possible to have a baby by having a donated egg implanted into your womb. This will need to be discussed with specialists at a centre that specialises in assisted reproduction techniques.

In women who have been through the menopause, both ovaries may be removed because they no longer produce eggs.

Make sure you discuss your fertility concerns with your surgeon before your operation.

Cancer treatment

If your test results show that your cyst is cancerous, both of your ovaries, your womb (uterus) and some of the surrounding tissue may need to be removed.

Again, this would trigger an early menopause and mean that you would no longer be able to get pregnant.

Read more about treating ovarian cancer