Each month during your menstrual cycle, a follicle grows on your ovary. A follicle is where an egg is developing. Most months, an egg is released from this follicle. This is 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.
Another type of cyst occurs after an egg has been released from a follicle. This is called a corpus luteum cyst. Such cysts often contain a small amount of blood.
Ovarian cysts are more common from puberty to menopause. This period of time is known as the childbearing years. Ovarian cysts are less common after menopause.
Taking fertility drugs can cause a condition in which multiple large cysts are formed on the ovaries. This is called ovarian hyperstimulation syndrome. The cysts usually go away after a woman's period, or after a pregnancy.
Functional ovarian cysts often don't need treatment. They usually go away on their own within 8 - 12 weeks.
If you have frequent cysts, your doctor or nurse may prescribe birth control pills (oral contraceptives). These medicines may reduce the risk of new ovarian cysts. Birth control pills do not decrease the size of current cysts.
Surgery to remove the cyst or ovary may be needed to make sure it isn't ovarian cancer. Surgery is more likely to be needed for:
Complex ovarian cysts that don't go away
Cysts that are causing symptoms and do not go away
Simple ovarian cysts that are larger than 5 - 10 centimeters
Bulun SE. The physiology and pathology of the femalereproductive axis. In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM, eds. Williams Textbook of Endocrinology. 12th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 17.
Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington. Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Bellevue, 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.