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

This article is about cysts that form during your monthly menstrual cycle, called functional cysts. Functional cysts are not the same as cysts caused by cancer or other diseases.

For more information about other causes of cysts on or near the ovaries, see also:

• Dermoid cyst
• Ectopic pregnancy
• Endometriosis
• Ovarian cancer
• Polycystic ovary syndrome

Causes

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.

Another type of cyst, called a corpus luteum cyst, occurs after an egg has been released from a follicle. These often contain a small amount of blood.

Ovarian cysts are somewhat common, and are more common during a woman's childbearing years (from puberty to menopause). Ovarian cysts are less common after menopause.

No known risk factors have been found.

Functional ovarian cysts are not the same as ovarian tumors (including ovarian cancer) or cysts due to hormone-related conditions such as polycystic ovary disease.

Taking fertility drugs can cause a condition called ovarian hyperstimulation, in which multiple large cysts are formed on the ovaries. These usually go away after a woman's period, or after a pregnancy.

Symptoms

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

An ovarian cyst is more likely to cause pain if it:

• Becomes large
• Bleeds
• Breaks open
• Is bumped during sexual intercourse
• Is twisted or causes twisting (torsion) of the Fallopian tube

Symptoms of ovarian cysts can 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 health care provider may discover a cyst during a physical exam, or when you have an ultrasound test for another reason.

Ultrasound is done on many patients to diagnose a cyst. Your doctor may want to check you again in 4 - 6 weeks to make sure it is gone.

Other imaging tests that may be done when needed include:

• CT scan
• Doppler flow studies
• MRI

Your health care provider may be able to feel the ovarian cyst during a pelvic exam.

The doctor may order the following blood tests:

• Ca-125 test, to look for possible cancer in women who have reached menopause or who have an abnormal ultrasound
• Hormone levels (such as LH, FSH, estradiol, and testosterone)
• Serum HCG (pregnancy test)

Treatment

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

Birth control pills (oral contraceptives) may be prescribed for 4 - 6 weeks. Longer-term use may decrease the development of new ovarian cysts. Birth control pills do not decrease the size of current cysts, which often will go away on their own.

Surgery to remove the cyst or ovary may be needed to make sure there are no cancer cells. 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
• Women who are menopausal or near menopause

Types of surgery for ovarian cysts include:

• Exploratory laparotomy
• Pelvic laparoscopy to remove the cyst or the ovary

The doctor may recommend other treatments if a disorder, such as polycystic ovary disease, is causing the ovarian cysts.

Outlook (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.

Possible Complications

Complications have to do with the condition causing the cysts. Complications can occur with cysts that:

• Bleed
• Break open
• Show signs of changes that could be cancer
• Twist

When to Contact a Medical Professional

Call for an appointment with your health care provider if:

• You have symptoms of an ovarian cyst
• You have severe pain
• You have bleeding that is not normal for you

Also call for an appointment if the following symptoms have been present on most days for at least 2 weeks:

• Getting full quickly when eating
• Losing your appetite
• Losing weight without trying

Prevention

If you are not trying to get pregnant and you often get functional cysts, you can prevent them by taking hormone medications (such as birth control pills), which prevent follicles from growing.

Alternative Names

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