Ovarian Cyst



The cause of ovarian cysts depends on the type of cyst. The type of cyst a person has depends on where it forms or what material is in it.

Functional cysts are the most common type. It is normal for cysts to develop as part of the ovulation cycle. They usually resolve on their own. The two types are:

  • Follicular cyst—Ovaries have a number of follicles (a fluid-filled sac) that each contain an egg. A follicle should release the egg during ovulation. A follicular cyst is caused by an egg that is not released. The cyst is made up of the follicle, trapped egg, and fluids.
  • Corpus luteum cyst—The egg is released, but the follicle closes up. This causes excess fluid to collect and create a cyst.

Less common types are:

  • Teratoma or dermoid cyst—May be present at birth or happen later in life. They contain tissue from other parts of the body, such as teeth and hair.
  • Endometrioma—Caused by endometriosis. Cysts may grow and become filled with fluid, often blood.
  • Cystadenoma—Grows from cells that line the outside of the ovary. Can become large and painful.

Some cysts can also be caused by pelvic infections that have spread to the ovaries.

Risk Factors

Cysts are more common in women with regular, monthly menstrual cycles. Other things that may raise the risk are:

  • Prior ovarian cysts
  • Hormonal changes during ovulation or in response to certain fertility medicines
  • Endometriosis
  • Pregnancy—a cyst is a normal part of early pregnancy but cysts that remain through pregnancy may cause problems
  • Severe pelvic infection



Most people do not have symptoms. Others may have:

  • Pelvic swelling
  • Pelvic pain and pressure
  • Problems emptying the bladder or bowel
  • Needing to urinate more often
  • Pain during sex
  • An ache in the legs or lower back
  • Unusual vaginal bleeding
  • Nausea and vomiting


The doctor will ask about symptoms and past health. A pelvic exam will be done. Cysts are often found during routine pelvic exams.

Other tests may be done to find out what type of cyst you have and whether treatment is needed.



Some cysts will go away in time without treatment. They may be watched for any changes.

Cysts that are causing problems will need to be treated. Surgery will be done to remove them. Sometimes the ovary will need to be removed as well. If both ovaries are removed, then menopause will begin right away.


There are no known guidelines to prevent an ovarian cyst.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.