Ovarian cysts are fluid-filled sacs or pockets within or on the surface of an ovary. The ovaries are two bilateral organs — each about the size and shape of an almond — located on each side of your uterus. Eggs (ova) develop and mature in the ovaries and are released in monthly cycles during your childbearing years. Many women have ovarian cysts at some time during their lives. Most ovarian cysts present little or no discomfort and are harmless. The majority of ovarian cysts disappear without treatment within a few months. However, ovarian cysts — especially those that have ruptured — sometimes produce serious symptoms. The best way to protect your health is to know the symptoms and types of ovarian cysts that may signal a more significant problem, and to schedule regular pelvic examinations.

Complications of Ovarian Cysts

A large ovarian cyst can cause abdominal discomfort. If a large cyst presses on your bladder, you may feel the need to urinate more frequently because bladder capacity is reduced. Some women develop less common types of cysts that may not produce symptoms, but that your doctor may find during a pelvic examination. Cystic ovarian masses that develop after menopause may be cancerous (malignant). These factors make regular pelvic examinations important.

The following types of cysts are much less common than functional cysts:

• Dermoid cysts. These cysts may contain tissue such as hair, skin or teeth because they form from cells that produce human eggs. They are rarely cancerous, but they can become large, causing the ovary to move out of its usual position in the pelvis. This increases the chance of painful twisting of your ovary, called ovarian torsion.
• Endometriomas. These cysts develop as a result of endometriosis, a condition in which uterine cells grow outside your uterus. Some of that tissue may attach to your ovary and form a growth.
• Cystadenomas. These cysts develop from ovarian tissue and may be filled with a watery liquid or a mucous material. They can become large — 12 inches or more in diameter — and lead to ovarian torsion.

Causes of Ovarian Cysts

Your ovaries normally grow cyst-like structures called follicles each month. Follicles produce the hormones estrogen and progesterone and release an egg when you ovulate. Sometimes a normal monthly follicle just keeps growing. When that happens, it becomes known as a functional cyst. This means it started during the normal function of your menstrual cycle. There are two types of functional cysts:

• Follicular cyst. Around the midpoint of your menstrual cycle, your brain's pituitary gland releases a surge of luteinizing hormone (LH), which signals the follicle holding your egg to release it. When everything goes according to plan, your egg bursts out of its follicle and begins its journey down the fallopian tube in search of sperm and fertilization.

A follicular cyst begins when the LH surge doesn't occur. The result is a follicle that doesn't rupture or release its egg. Instead it grows and turns into a cyst. Follicular cysts are usually harmless, rarely cause pain and often disappear on their own within two or three menstrual cycles.

• Corpus luteum cyst. When LH does surge and your egg is released, the ruptured follicle begins producing large quantities of estrogen and progesterone in preparation for conception. This changed follicle is now called the corpus luteum. Sometimes, however, the escape opening of the egg seals off and fluid accumulates inside the follicle, causing the corpus luteum to expand into a cyst.

Although this cyst usually disappears on its own in a few weeks, it can grow to almost 4 inches in diameter and has the potential to bleed into itself or cause the ovary to twist, cutting off its blood supply and causing pelvic or abdominal pain. If it fills with blood, the cyst may rupture, causing internal bleeding and sudden, sharp pain. The fertility drug clomiphene citrate (Clomid, Serophene), which is used to induce ovulation, increases the risk of a corpus luteum cyst developing after ovulation. These cysts don't prevent or threaten a resulting pregnancy.

Signs & Symptoms of Ovarian Cysts

You can't depend on symptoms alone to tell you if you have an ovarian cyst. In fact, you'll likely have no symptoms at all. Or if you do, the symptoms may be similar to those of other conditions, such as endometriosis, pelvic inflammatory disease, ectopic pregnancy or ovarian cancer. Even appendicitis and diverticulitis can produce signs and symptoms that mimic a ruptured ovarian cyst. Still, it's important to be watchful of any symptoms or changes in your body and to know which symptoms are serious. If you have an ovarian cyst, you may experience one or more of the following signs and symptoms:

Menstrual irregularities

• Pelvic pain — a constant or intermittent dull ache that may radiate to your lower back and thighs
• Pelvic pain shortly before your period begins or just before it ends
• Pelvic pain during intercourse (dyspareunia)
• Pain during bowel movements or pressure on your bowels
• Nausea, vomiting or breast tenderness similar to that experienced during pregnancy
• Fullness or heaviness in your abdomen
• Pressure on your rectum or bladder — difficulty emptying your bladder completely

Diagnosis of Ovarian Cysts

A cyst on your ovary may be found during a pelvic exam. If a cyst is suspected, doctors often advise further testing to determine its type and whether you need treatment.

Typically, doctors address several questions to determine a diagnosis and to aid in management decisions:

• Shape. Is your cyst irregularly shaped?
• Size. What size is it?
• Composition. Is it filled with fluid, solid or mixed? Fluid-filled cysts aren't likely to be cancerous. Those that are solid or mixed — filled with fluid and solid — may require further evaluation to determine if cancer is present.

To identify the type of cyst, your doctor may perform the following procedures:

• Pregnancy test. A positive pregnancy test may suggest that your cyst is a corpus luteum cyst, which can develop when the ruptured follicle that released your egg reseals and fills with fluid.
• Pelvic ultrasound. In this painless procedure, a wand-like device (transducer) is used to send and receive high-frequency sound waves (ultrasound). The transducer can be moved over your abdomen and inside your vagina, creating an image of your uterus and ovaries on a video screen. This image can then be photographed and analyzed by your doctor to confirm the presence of a cyst, help identify its location and determine whether it's solid, filled with fluid or mixed.
• Laparoscopy. Using a laparoscope — a slim, lighted instrument inserted into your abdomen through a small incision — your doctor can see your ovaries and remove the ovarian cyst.
• CA 125 blood test. Blood levels of a protein called cancer antigen 125 (CA 125) often are elevated in women with ovarian cancer. If you develop an ovarian cyst that is partially solid and you are at high risk of ovarian cancer, your doctor may test the level of CA 125 in your blood to determine whether your cyst could be cancerous. Elevated CA 125 levels can also occur in noncancerous conditions, such as endometriosis, uterine fibroids and pelvic inflammatory disease.

Treatments of Ovarian Cysts

Treatment depends on your age, the type and size of your cyst, and your symptoms. Your doctor may suggest:

• Watchful waiting. You can wait and be re-examined in one to three months if you're in your reproductive years, you have no symptoms and an ultrasound shows you have a simple, fluid-filled cyst. Your doctor will likely recommend that you get follow-up pelvic ultrasounds at periodic intervals to see if your cyst has changed in size.

Watchful waiting, including regular monitoring with ultrasound, is also a common treatment option recommended for postmenopausal women if a cyst is filled with fluid and is less than 2 centimeters in diameter.

• Birth control pills. Your doctor may recommend birth control pills to reduce the chance of new cysts developing in future menstrual cycles. Oral contraceptives offer the added benefit of significantly reducing your risk of ovarian cancer — the risk decreases the longer you take birth control pills.
• Surgery. Your doctor may suggest removal of a cyst if it is large, doesn't look like a functional cyst, is growing or persists through two or three menstrual cycles. Cysts that cause pain or other symptoms may be removed.

Some cysts can be removed without removing the ovary in a procedure known as a cystectomy. Your doctor may also suggest removing the affected ovary and leaving the other intact in a procedure known as oophorectomy. Both procedures may allow you to maintain your fertility if you're still in your childbearing years. Leaving at least one ovary intact also has the benefit of maintaining a source of estrogen production. If a cystic mass is cancerous, however, your doctor will advise a hysterectomy to remove both ovaries and your uterus. After menopause, the risk of a newly found cystic ovarian mass being cancerous increases. As a result, doctors more commonly recommend surgery when a cystic mass develops on the ovaries after menopause.

Prevention of Ovarian Cysts

Although there's no definite way to prevent the growth of ovarian cysts, regular pelvic examinations are a way to help ensure that changes in your ovaries are diagnosed as early as possible. In addition, be alert to changes in your monthly cycle, including symptoms that may accompany menstruation that aren't typical for you or that persists over more than a few cycles. Be sure to talk with your doctor about any concerns relating to menstruation.

When to seek Medical Advice

Seek immediate medical attention if you have:

• Sudden, severe abdominal or pelvic pain
• Pain accompanied by fever or vomiting

These signs and symptoms — or those of shock, such as cold, clammy skin, rapid breathing, and lightheadedness or weakness — indicate an emergency and mean that you need to see a doctor right away.