Ovarian cysts

What are ovarian cysts?

An ovarian cyst is a fluid filled sac that develops inside an ovary. It is very common, usually painless and will often go away without treatment. Ovarian cysts can affect women of any age. Most ovarian cysts are small, although some may reach a large size.

There are several different kinds of ovarian cyst, which are categorised as either:

Functional cysts (the most common type): harmless cysts that form as part of the menstrual cycle. Functional cysts are common in young women. They often disappear without treatment after a few weeks but rarely can rupture (burst) causing internal bleeding and sudden pain.

Pathological cysts: These are tumours in the ovaries that are either benign (harmless) or malignant (cancerous). 95 percent of the cysts in the ovaries are benign cysts.

A dermoid cyst, is the most common type of benign cyst in women who are under 40 years old. In women, over 40 years of age, a ‘cystadenoma’ is the most common type.

Dermoid cysts have the potential to grow very large. They can sometimes grow up to 15cm (6 inches) in diameter. They are not usually cancerous, but will usually need to be surgically removed.

Cystadenomas develop from cells that cover the outer part of the ovary. Serous cystadenomas do not usually grow very large, but they can cause symptoms if they rupture. In contrast, mucinous cystadenomas can grow very large (up to 30cm or 12 inches), filling up the inside of the abdomen and placing pressure on other organs, such as the bladder and bowel.

How common are ovarian cysts?

Ovarian cysts are very common. Ovarian cysts that cause symptoms are much less common, affecting only 1 in every 25 women at some point in their life.

Ovarian cysts and fertility

Ovarian cysts usually do not affect a woman’s ability to conceive. If the cyst is large and needs to be removed, it can usually be removed using laparoscopy (using ‘keyhole’ surgery). Only the cyst is removed with conservation of the remaining ovarian tissue in most of the cases.

What are the symptoms of ovarian cysts?

An ovarian cyst will usually cause symptoms if:

It ruptures.

It is very large.

It blocks the blood supply to the ovaries (torsion).

Under such circumstances, you may have the following symptoms:

Pelvic pain, which can range from a dull heavy sensation (associated with large cysts) to a sudden, sharp pain (which is associated with a ruptured cyst or torsion).

Difficulty emptying your bowels.

Pelvic pain during sexual intercourse.

A frequent need to urinate.

Changes to your normal menstruation – you may develop irregular periods, heavy periods or lighter periods than usual.

A feeling of fullness and bloating.

Indigestion or feeling very full even though you have only eaten a little.

Sometimes, ovarian cysts cause more serious problems, which are outlined below.

Torsion If a cyst is growing on a stem from an ovary, the stem can become twisted (called torsion). This stops the blood supply to the cyst and causes a lot of pain in the lower abdomen.

Bursting- The cyst may burst, causing sudden severe pain in the lower abdomen.

How are ovarian cysts diagnosed?

Most ovarian cysts do not cause any symptoms; therefore, they often can go undiagnosed. Sometimes, ovarian cysts are diagnosed by chance – for example, during a pelvic examination. They can also be spotted when people have an ultrasound scan for an unrelated reason.

Ultrasound scan: To confirm an ovarian cyst, you usually need to have an ultrasound scan. An ultrasound scan can usually confirm whether you have an ovarian cyst and how big it is.

MRI scan:  Further imaging with MRI may be needed in some cases.

Blood test: You may be referred for a blood test if an ultrasound scan shows that the cyst is partially solid, as opposed to being filled with fluid. The blood test will be used to measure levels of a protein called CA125, which is often elevated in cases of ovarian cancer. If your blood test shows a higher than normal level of CA125, it does not automatically mean that you have ovarian cancer because levels can fluctuate from person to person and it may be raised in some benign conditions also.

What is the treatment for ovarian cysts?

If you have an ovarian cyst, whether it needs to be treated or not will depend on:

Appearance and size of the cyst,

Your symptoms,

Your age (post-menopausal women have a slightly higher risk of developing ovarian cancer).

Options for the management of the cysts are:

Watchful waiting/Observation

In most cases, especially for simple cysts, a policy of ‘watchful waiting’ will be recommended where you receive no immediate treatment. This is because most cysts will disappear without the need for treatment. A follow-up ultrasound scan will usually confirm that this is the case.


If the cyst is large, or if it is causing symptoms, it will probably need to be removed. There are two types of operation, which are usually carried out under general anaesthetic (you will be asleep during the operation and will feel no pain). They are:


Cysts can mostly be removed using a surgical technique called a laparoscopy. This is a type of keyhole surgery where small cuts are made in your lower abdomen and the surgeon will be able to remove the cyst through the small cuts in your skin.

This is the preferred approach because it causes less pain, helps to preserve fertility and lets you resume normal activity sooner.


If there is a risk that the cyst is cancerous, a more invasive procedure called a laparotomy may be recommended. During a laparotomy, a larger cut is made to give the surgeon better access to the cyst.