Each month during your menstrual cycle, a follicle grows on your ovary. The follicle is where an egg is developing. 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.
Another type of cyst occurs after an egg has been released from a follicle. This is called a corpus luteum cyst. This type of cyst often contains a small amount of blood.
Ovarian cysts are more common the in childbearing years between puberty and menopause. The condition is 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 most often go away after a woman's period, or after a pregnancy.
Functional ovarian cysts are not the same as ovarian tumors, or cysts due to hormone-related conditions such as polycystic ovary syndrome.
Ovarian cysts often cause no symptoms.
An ovarian cyst is more likely to cause pain if it:
Interferes with the blood supply to the ovary
Is bumped during sexual intercourse
Is twisted or causes twisting (torsion) of the Fallopian tube
Symptoms of ovarian cysts can also include:
Bloating or swelling in the abdomen
Pain during bowel movements
Pain in the pelvis shortly before or after beginning a menstrual period
Pain with intercourse or pelvic pain during movement
Pelvic pain -- constant, dull aching
Sudden and severe pelvic pain, often with nausea and vomiting, may be a sign of torsion or twisting of the ovary on its blood supply, or rupture of a cyst with internal bleeding
Changes in menstrual periods are not common with follicular cysts, and are more common with corpus luteum cysts. Spotting or bleeding may occur with some cysts.
Exams and Tests
Your doctor or nurse may discover a cyst during a pelvic exam, or when you have an ultrasound test for another reason.
Ultrasound may be done to diagnose a cyst. Your doctor or nurse may want to check you again in 6 - 8 weeks to make sure it is gone.
Other imaging tests that may be done when needed include:
Functional ovarian cysts often do not need treatment. They often 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 that it is not ovarian cancer. Surgery is more likely to be needed for:
Complex ovarian cysts that do not go away
Cysts that are causing symptoms and do not go away
Simple ovarian cysts that are larger than 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.
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, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.