Overview
An ovarian cyst is a fluid-filled sac that forms on or inside an ovary, and it can affect one or both ovaries. Cysts are very common. Most cause no symptoms, are found by chance and disappear within a few months without treatment.
There are two main kinds. Functional cysts form as part of the monthly cycle and are usually harmless. Pathological cysts come from abnormal cell growth and are much less common. Most cysts are non-cancerous, but a small number are cancerous.
Symptoms
Most cysts cause no symptoms. They are more likely to if they burst, grow very large or twist and cut off the ovary's blood supply. Possible symptoms are:
- Pelvic pain, from a dull, heavy ache to sudden, severe, sharp pain
- Pain during sex
- Difficulty emptying the bowels, or needing to pass urine more often
- Heavy, irregular or lighter periods than usual
- Bloating, a swollen tummy, or feeling full after eating very little
- Difficulty becoming pregnant
When to see a doctor
See a doctor if you have symptoms that could be an ovarian cyst, if a known cyst gives you more symptoms, or if you have been trying to become pregnant without success. After the menopause, see a doctor promptly about any of these.
Causes
Functional cysts are part of the menstrual cycle. Each month an egg grows inside a small fluid-filled sac called a follicle. A cyst forms if the follicle does not release its egg or does not shrink afterwards, and most disappear within a few months.
Other cysts come from abnormal cell growth or other conditions. In endometriosis, tissue like the womb lining grows on the ovary and can form blood-filled cysts. Polycystic ovary syndrome (PCOS) causes many small cysts because of hormone changes.
Risk factors
- Still having periods: functional cysts form with the monthly cycle
- Endometriosis or polycystic ovary syndrome
- Being past the menopause, when a cyst is slightly more likely to be cancerous
Complications
- A cyst that bursts (ruptures), causing sudden pain and sometimes bleeding
- A cyst that twists and cuts off the ovary's blood supply, causing sudden severe pain that needs urgent treatment
- A very large cyst causing pressure, bloating or pain
- Rarely, a cancerous cyst, more likely after the menopause
Prevention
Cysts that come with the monthly cycle cannot be prevented. Some women are advised birth control pills, which can help prevent new cysts.
Diagnosis
The doctor will ask about your symptoms and may examine your tummy and pelvis. The usual test is an scan, often with a thin probe passed inside the vagina. The scan may be repeated after a few weeks, or you may be sent to a gynaecologist.
If cancer is a worry, blood tests can look for raised chemical levels, but endometriosis, fibroids and even your period can raise them too.
Treatment
Treatment depends on the size and look of the cyst, whether it causes symptoms and whether you have been through the menopause.
- Watching and waiting: most cysts need no treatment, and a repeat scan after some weeks or months shows whether it has gone
- Keyhole surgery (laparoscopy) through small cuts, for a cyst that is large, painful, does not go away or may be cancerous
- Open surgery through a larger cut, for a very large cyst or if cancer is suspected
- After the menopause: regular scans and blood tests over about a year
Before the menopause the surgeon will try to keep as much of your reproductive system as possible. Removing only the cyst usually leaves both ovaries in place, so fertility should be unaffected. A burst or twisted cyst needs prompt treatment, often surgery.
Myths and facts
Things people often say about this. Open each one to see what is true.
Myth“Every ovarian cyst has to be operated on.”What is true?
Fact
Most cysts disappear within a few months without treatment. Often the doctor just repeats the scan after some weeks or months. Surgery is advised if a cyst is large, causes symptoms, does not go away or might be cancerous.
Myth“An ovarian cyst means cancer.”What is true?
Fact
Most cysts are non-cancerous. A small number are cancerous, and these are more common after the menopause, which is why a cyst found after the menopause is followed with scans and blood tests over about a year.
Myth“With a cyst on the ovary you cannot get pregnant.”What is true?
Fact
Cysts do not usually prevent pregnancy, although they can sometimes make it harder to conceive. Fertility is usually not affected.
Myth“If a cyst needs surgery, the whole ovary or womb is taken out.”What is true?
Fact
Before the menopause, surgeons try to keep as much of the reproductive system as possible. Often only the cyst is removed, through small cuts, and both ovaries stay in place. Talk to your surgeon about fertility before any operation.
Myth“Cysts come from eating the wrong food or from something you did.”What is true?
Fact
The most common type forms as part of the normal monthly cycle, when the small sac that holds an egg does not release it, or does not drain and shrink afterwards. Others are linked to conditions such as endometriosis or polycystic ovary syndrome.
Questions to ask your doctor
Tick the ones you want answered and take them with you.
Common questions
Will an ovarian cyst go away by itself?
Often, yes. Most cysts disappear within a few months without treatment, especially the common type that forms with the monthly cycle. The doctor may repeat the scan to check that it has gone.
Does a cyst affect having a baby?
Cysts do not usually prevent pregnancy, but they can sometimes make it harder to conceive. If an operation is needed, surgeons try to protect your fertility. Tell the doctor if you want to become pregnant.
How will I know if a cyst has burst or twisted?
The usual sign is sudden, severe pain in the pelvis or tummy, sometimes with nausea or vomiting. That needs emergency care, so do not wait to see if it settles.
Why do I need scans after the menopause?
Cancerous cysts are more common after the menopause, and the risk of ovarian cancer is slightly higher. Doctors follow a cyst with scans and blood tests over about a year to make sure it is safe.