Ovarian cysts are fluid-filled pockets in an ovary or on its surface. Women have two ovaries — each about the area and shape of an almond — on each side of the uterus. Eggs (ova), which develop and mature in the ovaries, are released in monthly cycles during the childbearing years.

Many women have ovarian cysts at some time. Most ovarian cysts present little or no discomfort and are harmless. The majority disappears without treatment within a few months.

However, ovarian cysts — primarily those that have ruptured — can cause serious symptoms. To guard your health, get routine pelvic exams and know the symptoms that can signal a potentially serious problem.

Most cysts don’t cause symptoms and go away on their own. However, a large ovarian cyst can cause:

• Pelvic pain — a dull or fine ache in the lower abdomen on the side of the cyst
• Fullness or heaviness in your abdomen
• Bloating

When to see a doctor

Seek immediate medical attention if you have:

• Sudden, severe abdominal or pelvic pain
• Pain with fever or vomiting

If you have these signs or those of shock — cold, clammy skin; rapid breathing; and lightheadedness or weakness — see a doctor right away.

Follicular cystOpen pop-up dialog box

Corpus luteumcystOpen pop-up dialog box

Most ovarian cysts improve as a result of your menstrual cycle (functional cysts). Other types of cysts are much less common.

Functional cysts:

Your ovaries normally raise cyst-like structures called follicles each month. Follicles produce the hormones estrogen and progesterone and release an egg when you ovulate.

If a normal monthly follicle keeps growing, it’s known as a functional cyst. There are two types of functional cysts:

• Follicular cyst. Around the midpoint of your menstrual an egg bursts out of its follicle and travels down the fallopian tube. A follicular cyst begins when the follicle doesn’t rupture or release its egg but continues to grow.
• Corpus luteum cyst. When a follicle loses its egg, it begins generating estrogen and progesterone for conception. This follicle is now called the corpus luteum. Sometimes, fluid accumulates inside the follicle, making the corpus luteum grow into a cyst.

Functional cysts are normally harmless, rarely cause pain, and often disappear on their own within two or three menstrual cycles.

Other cysts

Types of cysts not correlated to the common function of your menstrual cycle include:

• Dermoid cysts. Also called teratomas, these can contain tissue, such as hair, skin, or teeth because they form embryonic cells. They’re rarely cancerous.
• Cystadenomas. These develop on the surface of an ovary and might be filled with a watery or a mucous material.
• Endometriomas. These develop as a result of a condition in which uterine endometrial cells grow outside your uterus (endometriosis). Some of the tissue can attach to your ovary and form growth.

Dermoid cysts and cystadenomas can become large, causing the ovary to go out of position. This improves the chance of painful twisting of your ovary, called ovarian torsion.

Your risk of improving an ovarian cyst is heightened by:

• Hormonal problems. These include using the fertility drug clomiphene (Clomid), which is used to cause you to ovulate.
• Pregnancy. Sometimes, the cyst that appears when you ovulate stays on your ovary throughout your pregnancy.
• Endometriosis. This situation causes uterine endometrial cells to grow outside your uterus. Some of the tissue can attach to your ovary and form growth.
• A severe pelvic infection. If the infection grows to the ovaries, it can cause cysts.
• A previous ovarian cyst. If you’ve had one, you’re likely to produce more.

Some women improve less common types of cysts that a doctor finds during a pelvic exam. Cystic ovarian masses that increase after menopause might be cancerous (malignant). That’s why it’s important to have routine pelvic exams.

Infrequent complications associated with ovarian cysts include:

• Ovarian torsion. Cysts that enlarge can cause the ovary to move, increasing the chance of painful twisting of your ovary (ovarian torsion). Symptoms can include an abrupt onset of severe pelvic pain, nausea, and vomiting. Ovarian torsion can also decrease or stop blood flow to the ovaries.
• Rupture. A cyst that ruptures can produce severe pain and internal bleeding. The kinder the cyst, the higher the risk of rupture. A vigorous movement that affects the pelvis, such as vaginal intercourse, also increases the risk.