An ovarian cyst is a fluid-filled sac that develops on a woman's ovary. They're very common and don't usually cause any symptoms.
Most ovarian cysts occur naturally and disappear in a few months without needing any treatment.
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:
- 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 cyst 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
- pathological ovarian cysts – cysts that form as a result of 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.
Treating ovarian cysts
Whether an ovarian cyst needs to be treated will depend on:
- its size and appearance
- whether you have any symptoms
- whether you've 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.
As post-menopausal women have a slightly higher risk of ovarian cancer, regular ultrasound scans and blood tests are usually recommended over the course of a year to monitor the cyst.
Surgical treatment to remove the cysts may be needed if they're large, causing symptoms, or potentially cancerous.
Read more about treating ovarian cysts .
Ovarian cysts and 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'll no longer produce any eggs. Make sure you talk to your surgeon about the potential effects on your fertility before your operation.
An ovarian cyst usually only causes symptoms if it splits (ruptures), is very large, or 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 ovarian cysts and fertility)
See your doctor if you have persistent symptoms of an ovarian cyst.
If you have sudden, severe pelvic pain you should immediately contact either:
- your doctor or local out-of-hours service
- non-emergency medical services by telephone
- your nearest accident and emergency (A&E) department
Causes and types
Ovarian cysts often develop naturally in women who have monthly periods.
They can also affect women who have been through the menopause.
Types of ovarian cyst
There are many different types of ovarian cyst, which can be categorised as either:
- functional cysts
- pathological cysts
Functional ovarian cysts are linked to the menstrual cycle. They affect girls and women who haven't 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 doesn't release an egg, or it doesn't discharge its fluid and shrink after the egg is released. If this happens, the follicle can swell and become a cyst.
Functional cysts are non-cancerous (benign) and are usually harmless, although they can sometimes cause symptoms such as pelvic pain. Most will disappear in a few months without needing any treatment.
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 often surgically removed.
Conditions that cause ovarian cysts
In some cases, ovarian cysts are caused by an underlying condition 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 don't grow to ovulation and are the result of altered hormone levels.
If your doctor 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 doctor may refer you to a gynaecologist (a doctor who specialises in female reproductive health).If there's 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:
- a pelvic infection
- your period
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've had the menopause – as post-menopausal women have a slightly higher risk of ovarian cancer
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.
Women who have been through the menopause may be advised to have ultrasound scans and blood tests every four months for a year, as they have a slightly higher risk of ovarian cancer.
If the scans show that the cyst has disappeared, further tests and treatment aren't usually necessary. Surgery may be recommended if the cyst is still there.
Large or persistent ovarian cysts, or cysts that are causing symptoms, usually need to be surgically removed.
Surgery is also normally 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 .
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.
If your cyst is particularly large, or there's 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 the ovarian cyst has been removed, you'll feel pain in your tummy, although this should improve in a day or two.
Following laparoscopic surgery, you'll probably need to take things easy for two weeks. Recovery after a laparotomy usually takes 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 doctor 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.
If you haven't 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 haven't been through the menopause. This triggers an early menopause and means 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.
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.
This would trigger an early menopause and mean that you're no longer be able to get pregnant.
Read more about treating ovarian cancer .