Ovarian cysts

Alternative Names

Physiologic ovarian cysts; Functional ovarian cysts; Corpus luteum cysts; Follicular cysts

Definition of Ovarian cysts

An ovarian cyst is a sac filled with fluid that forms on or inside of an ovary.

Causes, incidence, and risk factors

Each month during your menstrual cycle, a follicle (where the egg is developing) grows on your ovary. Most months, an egg is released from this follicle (called ovulation). If the follicle fails to break open and release an egg, the fluid stays in the follicle and forms a cyst.This is called a follicular cyst.


Ovarian cysts often cause no symptoms. When symptoms occur, they are typically pain or a late period.

Signs and tests

Your health care provider may discover a cyst during a physical exam, or when you have an ultrasound test for another reason.


Functional ovarian cysts usually don’t need treatment. They usually disappear within 8 – 12 weeks without treatment.

Expectations (prognosis)

Cysts in women who are still having periods are more likely to go away. There is a higher risk of cancer in women who are postmenopausal.


Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Redmond, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. – 3/30/2010

Female reproductive anatomy
Ovarian cysts
Uterine anatomy

ADAM Medical Encyclopedia

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