Hearing the word "cyst" after an ultrasound can be unsettling. Many people immediately wonder whether it means cancer, surgery or trouble getting pregnant. In most cases, the answer is reassuring. The American College of Obstetricians and Gynecologists (ACOG) describes ovarian cysts as "very common," and says most are benign and go away on their own without treatment.

What is an ovarian cyst?

ACOG defines an ovarian cyst as a sac or pouch filled with fluid or other tissue that forms in or on an ovary. Cysts can occur during the reproductive years or after menopause. Most are not cancer. Rarely, a cyst can be malignant, and there are also benign ovarian tumors that can look like cysts on imaging.

Because cysts are so common and so often harmless, many are found by chance during a routine pelvic exam or an imaging test done for another reason.

The main types

ACOG describes four main types of ovarian cyst.

Functional cysts

These are the most common type. They are linked to the normal workings of the menstrual cycle, which is where the name comes from. Functional cysts usually cause no symptoms, and ACOG says they often go away without treatment within 6 to 8 weeks.

Teratomas

A teratoma is a cyst or benign tumor that contains different kinds of body tissue, such as skin and hair. Teratomas may be present from birth and can grow during the reproductive years. In very rare cases, ACOG notes, some teratomas can become cancer.

Cystadenomas

A cystadenoma is a benign tumor that forms on the outer surface of the ovary. These can grow very large even though they are usually benign.

Endometriomas

An endometrioma is a cyst that forms as a result of endometriosis, a condition where tissue similar to the lining of the uterus grows outside the uterus. If you have endometriosis or suspect you might, our guide to endometriosis symptoms, diagnosis and treatment covers it in depth.

What about PCOS?

Polycystic ovary syndrome is a different condition, despite the name. It involves hormonal changes and many small follicles on the ovaries rather than the kinds of cysts described above. Our complete guide to PCOS explains the difference.

Symptoms

ACOG notes that in most cases cysts do not cause symptoms at all. When they do, possible symptoms include:

  • A dull or sharp ache in the abdomen
  • Pain during certain activities

Symptoms that need urgent care

Two complications deserve special attention.

Ovarian torsion. ACOG explains that larger cysts can cause the ovary to twist. This may cause pain on one side that comes and goes, or pain that starts suddenly. Torsion can cut off blood supply to the ovary, so sudden one sided pelvic pain should be checked promptly.

A cyst that bleeds or bursts. ACOG says this can cause sudden, severe pain.

If you have sudden, severe pelvic or abdominal pain, especially with fever, vomiting, dizziness or fainting, seek emergency care.

How cysts are diagnosed

If your ob gyn thinks you may have a cyst, ACOG says tests may include:

Ultrasound. Sound waves create pictures of the internal organs. A small instrument called a transducer is placed in the vagina or on the abdomen. The images show the shape, size and location of the cyst, and whether it is solid or filled with fluid. These features help your doctor judge what type of cyst it is likely to be.

Blood tests. A blood test may measure a substance called CA 125. ACOG explains that an increased level, together with certain ultrasound and exam findings, may raise concern for ovarian cancer, especially after menopause. CA 125 can be raised for other reasons too, so it is interpreted alongside the rest of the picture rather than on its own. Several other blood tests can also help assess whether a mass is concerning.

Treatment options

The right approach depends on the type of cyst and other factors. ACOG describes two broad options: watchful waiting and, if the cyst is large or causing symptoms, surgery.

Watchful waiting

Watchful waiting means monitoring the cyst with repeat ultrasounds to see whether it changes in size or appearance. Your ob gyn will recommend when to repeat the scan and how long follow up should last. ACOG notes that many cysts go away on their own after one or two menstrual cycles.

For many people, this is the whole story: a cyst is found, it is checked again a couple of months later and it is gone.

Surgery

ACOG says surgery may be recommended if a cyst is very large, causing symptoms or if cancer is suspected. The choice of surgery depends on the size of the cyst, your age, whether you want to have children in the future and whether you have a family history of ovarian or breast cancer.

There are two main operations:

  • Cystectomy: removing the cyst while leaving the ovary.
  • Oophorectomy: removing the ovary, which is sometimes necessary.

If the cyst is thought to be benign, ACOG says minimally invasive surgery is recommended. This is usually laparoscopy, done through small incisions with a thin lighted instrument called a laparoscope. Open surgery, through a larger incision in the lower abdomen, may be done if cancer is suspected or if the cyst is too large for laparoscopy. If cancer is suspected, it is important to remove the cyst intact, and sometimes open surgery is the only way to do that.

Questions to ask your doctor

If you have been told you have an ovarian cyst, these questions can help you understand your situation:

  1. What type of cyst does this look like?
  2. How big is it, and is it fluid filled or solid?
  3. Do you recommend watchful waiting, and when should I have the next scan?
  4. What symptoms should make me call you or go to the emergency room?
  5. If surgery is needed, can the ovary be preserved?
  6. Does this affect my fertility or my choice of contraception?

Writing down your symptoms, including when pain happens and where in your cycle you are, can also help. Our menstrual cycle tracker makes that easier.

After menopause

Cysts can still occur after menopause. Because the risk of ovarian cancer is higher later in life, ACOG notes that a raised CA 125 level is more concerning after menopause, and your doctor may recommend closer follow up. Most cysts found after menopause are still benign, but they are taken seriously.

The takeaway

Ovarian cysts are very common and usually harmless. Functional cysts, the most common kind, often disappear within weeks without treatment. Ultrasound and sometimes blood tests help your doctor decide whether to watch and wait or to treat. Sudden or severe pelvic pain, which can signal a twisted ovary or a burst cyst, needs urgent care. For everything else, regular follow up and a clear plan with your ob gyn are usually all you need.

This article is for general information and is not a substitute for medical advice. Talk to your health care professional about your own situation.

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