Ovarian Cysts

Ovarian cysts are fluid-filled sacs or pockets within or on the surface of one of the ovaries. Many women will develop them at some time during their lives and they are usually discovered during routine pelvic examinations. Most ovarian cysts are painless and cause no symptoms, usually disappearing on their own without the need for medical attention.

There are two main types of ovarian cyst: functional and pathological.

Functional Cysts functional ovarian cyst

Most ovarian cysts develop as a result of the normal function of the menstrual cycle. These are known as functional cysts and are the most common type. Functional cysts are usually harmless, rarely cause pain and often disappear on their own within two or three menstrual cycles.

 There are two types of functional cysts; follicle and corpus luteum. 

Follicle Cysts

During the menstrual cycle, an egg grows inside a sac located inside the ovaries, which is called a follicle. Generally, this follicle will break open to release an egg, but if this does not happen, the fluid found inside the follicle may produce a cyst on the ovary.

Corpus Luteum Cysts

Normally, follicle sacs will dissolve after to release of an egg. However, if the sac does not dissolve and the follicle seals, then extra fluid may develop inside of the sac, causing a corpus luteum cyst.

Pathological Ovarian Cysts

These type of cysts are far more uncommon and have formed as a result of an abnormal cell growth, rather than the normal function of your menstrual cycle.

These cysts include; dermoid cysts, cystadenomas and endometriomas.

Dermoid Cysts

These are cysts which contain tissue, such as hair, skin, fatty tissue or teeth and can grow quite large. This type of cyst develops from cells which make eggs in the ovary and has the possibility to develop into any type of cell. They should be surgically removed.


These cysts develop from cells which cover the outer layer of the ovary and may be filled with a watery liquid or a mucous material. Instead of growing inside the ovary, cystadenomas are typically attached by a stalk to the ovary and as such, they can grow to a very large size. Most are benign and therefore not cancerous, though they should still be surgically removed.

Both dermoid cysts and cystadenomas can grow exceptionally large in size and cause ovarian torsion, which is a very painful twisting of the ovary caused by the growth blocking the blood supply.


These cysts develop as a result of endometriosis, a condition in which uterine endometrial tissue grow outside the womb, causing cysts on the ovaries. Endometriomas may also be referred to as chocolate cysts, since the blood found within the cysts look like chocolate.

Ovarian cyst symptoms

Ovarian cysts usually occur naturally and do not cause problems, unless they split or rupture, are particularly large in size or are blocking the blood supply to the ovaries.

woman with abdominal pain

In any of the above cases, symptoms may include:

  • Pelvic/abdominal pain or discomfort
  • Painful intercourse
  • Abdominal distension (swelling)
  • Difficulty passing urine or frequent need to urinate
  • Abnormal bleeding or irregular periods
  • Difficulty emptying the bowels
  • Bloating
  • Feeling of fullness after only eating small amount
  • Difficulty falling pregnant


Since most ovarian cysts show no symptoms or signs, they often go undiagnosed. Most are found during unrelated routine pelvic examinations or ultrasounds. However, if a woman is experiencing any symptoms of ovarian cysts, an examination and diagnosis can be made in several ways.

Pelvic ultrasound

An ultrasound scan can be carried out to confirm the presence of a cyst, help identify its location and determine the consistency (if it is sold or filled with fluid). This involves placing a probe inside the vagina and a wand-like scanner (transducer) over the abdomen, where the ovaries are. Like a pregnancy ultrasound, the doctor observes the internal organs on a screen.

If a cyst is found during the ultrasound, this may be monitored and a repeat ultrasound carried out a few weeks later, or your GP may immediately refer you to a specialist gynaecologist if necessary.


CT or MRI scans

An MRI or CT scan may sometimes be necessary if an ultrasound is inconclusive regarding the location or nature of the cyst. MRI scans use magnetic waves to produce detailed images of internal organs. CT scans use body imaging devices to create cross-sectional images of the internal organs. Both can provide more in-depth analysis and diagnosis of medical issues.

CA125 blood test

Where there is a tumour present, the blood levels of the CA125 protein are often elevated, which could signal ovarian cancer. As such, this blood test is used to help determine whether an ovarian cyst could be cancerous. However, elevated CA125 levels can also occur in non-cancerous conditions, such as endometriosis, uterine fibroids and pelvic inflammatory disease.


Treatment of an ovarian cyst depends upon its cause, size and appearance, whether the patient is experiencing symptoms and whether she has been through menopause.

Doctor talking to patient

Possible treatments include:

Watchful waiting – In cases of small, simple cysts it is recommended that an ultrasound scan is undertaken every three months to monitor the cysts and detect any changes. This is known as the ‘watchful waiting’ approach. Cysts might typically remain the same size, get smaller, or even disappear. In those cases, you usually do not need any treatment.

Contraceptive pills – These are used to stop ovulation and can, therefore, help prevent some types of new cysts from developing. They can also help reduce the risk of developing ovarian cancer.

Surgery – Can be carried out to remove the cyst or the whole ovary. If a cyst is bigger than normal, causing symptoms or appears suspicious for cancer, surgery may be the best option. In the vast majority of cysts, the operation is carried out via keyhole surgery (laparoscopy).


Find out more about treatments for ovarian cysts