Understanding Ovarian Cysts

An ovarian cyst is a fluid-filled sac that forms on or inside an ovary. The ovaries are a pair of small, oval-shaped organs in the lower part of a woman’s belly (abdomen). About once a month, one of the ovaries releases an egg. The ovaries also make the hormones estrogen and progesterone. These hormones are part of pregnancy, the menstrual cycle, and breast growth.

Ovarian cysts are very common in women of all ages. Young girls can also get them, but this is less common. There are different types of ovarian cysts. They can occur for various reasons, and they may need different treatments. A cyst can vary in size from half an inch to more than 4 inches.

Types of ovarian cysts

There are different types of ovarian cysts:

Functional cyst

This is the most common type of ovarian cyst. They only occur in women who haven’t gone through menopause. There are 2 types of functional cysts:

  • Follicular cyst. This cyst happens when an egg isn’t released and it keeps growing inside the ovary.

  • Corpus luteum cyst. This type of cyst occurs when the sac around the egg doesn’t dissolve after the egg is released.


This is a cyst filled with old blood and tissue from the lining of the uterus. They are often called chocolate cysts because of their dark color. They can happen in women with endometriosis.

Dermoid cyst

This cyst develops from ovarian cells and eggs. They may have hair, skin, or fat in them. These cysts are common in women of childbearing age.

What causes ovarian cysts?

Cysts can also be caused by:

  • Polycystic ovary syndrome (PCOS), a condition that causes multiple cysts on the ovaries

  • Pregnancy

  • Severe pelvic infection, such as chlamydia

  • Noncancerous growths

  • Cancer (rare)

  • Using fertility medicine to cause ovulation, such as clomiphene

Symptoms of an ovarian cyst

Many women don’t have any symptoms from the cyst. In women with symptoms, the most common is pain or pressure in your lower belly on the side of the cyst. This pain may be dull or sharp, and it may come and go. A cyst that breaks open (ruptures) may lead to sudden, sharp pain.

Other symptoms of an ovarian cyst can include:

  • Pain in the lower back or thighs

  • Trouble emptying your bladder fully

  • Pain during sex

  • Weight gain

  • Pain during your period

  • Breast tenderness

  • Abnormal vaginal bleeding (rare)

Diagnosing an ovarian cyst

Your primary care doctor or an obstetrics and gynecology (OB/GYN) doctor may diagnose the condition. Your doctor will ask about your health history and your symptoms. You will also have a physical exam. This will likely include a pelvic exam. During the pelvic exam, your doctor may feel the swelling on your ovary. In women with no symptoms, this is often the first sign of a cyst.

If your doctor thinks you may have an ovarian cyst, you may need tests. These can help your doctor learn the type of cyst. Tests can also help rule out other problems, such as an ectopic pregnancy. The tests may include:

  • Ultrasound. This test uses sound waves to view the size, shape, and location of the cyst. The test can also show if the growth is solid or filled with fluid.

  • MRI. This uses large magnets and a computer to create a detailed picture of the area.

  • Pregnancy test. This is done to check if pregnancy may be the cause of the cyst.

  • Blood tests. These check for hormone problems and cancer. They also check if the cyst is bleeding.

  • Biopsy. This is a test where a tiny piece of the ovary is taken. The piece is examined in a lab for cancer cells. This may be done if an ultrasound shows a certain type of growth on the ovary.