The size of your ovaries can change throughout your menstrual cycle. In some cases, enlarged ovaries may indicate an ovarian cyst or another condition requiring treatment.

Your ovaries are part of your reproductive system. They have two main jobs:

  • produce and release eggs for fertilization
  • make the hormones estrogen and progesterone

There are several reasons why your ovaries might become enlarged, or swollen. Some causes of enlarged ovaries are harmless. During your menstrual cycle, your ovary naturally swells up as an egg matures and prepares for release. Fluid-filled sacs called cysts that form in the ovaries are another possible reason for these organs to swell up.

Later in life, enlarged ovaries could be a sign of ovarian cancer. This is serious. Ovarian cancer is rare overall, so it’s an unlikely cause of swelling. Still, it’s important to see your doctor for imaging scans to find out for sure what’s going on.

Keep reading to learn what symptoms to watch for, what treatment options are available, and when to see your doctor.

Ovulation is the part of your menstrual cycle when your ovary releases an egg. It happens at about the midpoint (day 14) of your cycle.

Right before you ovulate, follicles in your ovaries swell up as the eggs grow and get ready to be released.

Other signs of ovulation include:

  • an increase or change in vaginal discharge
  • a slight increase in body temperature
  • slight cramping

What you can do

You don’t have to do anything to address ovulation. In this case, ovarian enlargement is a normal part of your menstrual cycle. The swelling will go down once an egg is released.

Ovarian cysts are fluid-filled sacs that form in the ovaries. They’re very common. According to the Cleveland Clinic, they affect up to 18 percent of women.

Cysts can cause the ovaries to swell up — especially if they’re large or you have a lot of them. There are three different types of ovarian cysts:

Corpus luteum cyst

Follicles normally dissolve once they’ve released an egg. Sometimes a follicle doesn’t dissolve and the opening to the follicle doesn’t close up properly. Fluid can build up inside the sac and form a type of cyst called corpus luteum.

Dermoid cyst

A dermoid cyst contains tissues that are normally found in other parts of your body. This includes your hair follicles, oil glands, or sweat glands. These tissues release their normal substances inside your ovary, which can make it swell up.

Dermoid cysts form as an embryo is developing. Skin, sweat glands, and other tissue become trapped inside the skin as it grows. These cysts are usually harmless and don’t cause symptoms. Doctors often discover them while doing an imaging scan or surgery for another reason.

Follicular cyst

A follicular cyst forms when a follicle doesn’t release its egg during ovulation. Instead, it grows and turns into a cyst. Follicular cysts typically don’t have any symptoms. They go away on their own.

What you can do

Most ovarian cysts don’t cause any problems. They’ll usually go away within a few months without any treatment. If cysts are large enough to cause symptoms like pain and bloating, or if they burst, you may need surgery to have them removed. Your doctor may also prescribe birth control pills to prevent future ovarian cysts.

Ovarian torsion occurs when the ovary and part of the fallopian tube twists around. It often happens because of a cyst or other growth on the ovary. Sometimes a woman’s ovaries twist because they’re more flexible than the average ovary.

Ovarian torsion is most likely to affect a woman during her reproductive years.

Symptoms of ovarian torsion include:

  • pain in the lower belly and pelvis, which can come and go or be continuous
  • nausea
  • vomiting

What you can do

Ovarian torsion is a medical emergency. The twisting can cut off blood flow to the ovary, causing the tissue to die and the ovary to become infected.

If you have this condition, you’ll need surgery right away to either untwist the ovary or remove the ovary and fallopian tube.

An endometrioma is an ovarian cyst that forms from endometrial tissue. This is the same tissue that lines the uterus. It affects women with endometriosis. Endometriosis is a condition in which endometrial tissue implants in different parts of the pelvis.

The tissue lining your uterus normally swells up each month and sheds during your period. When the same tissue is in your ovaries, it swells up but has nowhere to shed.

Between 20 and 40 percent of women with endometriosis develop endometriomas, according to the Endometriosis Foundation of America.

Symptoms of endometriosis — and endometriomas — include:

  • abdominal pain
  • painful periods
  • pain during sex
  • pain when you urinate or have a bowel movement
  • heavy bleeding during periods or bleeding in between periods

If left untreated, endometriomas can damage your ovaries to the point where you can’t get pregnant. These growths can also increase your risk for ovarian cancer. See your doctor right away if you’re experiencing symptoms.

What you can do

Your doctor can perform surgery to remove the endometrioma. Another option is to remove the whole ovary. However, this surgery typically isn’t done in women who are of reproductive age because it affects fertility.

Polycystic ovary syndrome (PCOS) is a condition in which a woman has higher than normal levels of male hormones called androgens. These excess hormones can cause cysts to form in the ovaries and make the ovaries swell up.

PCOS symptoms usually start around the time of puberty and can include:

  • fewer periods than usual
  • heavy periods
  • weight gain
  • pelvic pain
  • fatigue
  • facial hair and excess body hair
  • acne
  • thinning hair on the head
  • mood changes
  • difficulty getting pregnant
  • trouble sleeping

What you can do

Treatments address the symptoms of PCOS, but they don’t cure the condition.

Your doctor might prescribe:

  • birth control pills containing the hormones estrogen and progestin, or progestin only, to regulate your menstrual cycle
  • drugs like clomiphene (Clomid), letrozole (Femara), or gonadotropins to help you ovulate and get pregnant
  • spironolactone (Aldactone), eflornithine (Vaniqa), or birth control pills to reduce unwanted hair growth

If you’re overweight, losing 5 to 10 percent of your body weight can help normalize your periods and make you ovulate. Talk to your doctor about the ideal weight for you and what you can do to achieve your diet and fitness goals.

Tumors can grow inside the ovary. Most are noncancerous — or benign — and never spread beyond the ovary.

Fibromas are a type of ovarian tumor made from connective tissues. These tumors usually grow slowly.

Most noncancerous tumors don’t cause symptoms. If you do have symptoms, they might include:

  • aching or pain in the pelvis
  • a feeling of pressure or heaviness in the abdomen
  • pain during sex
  • fever
  • nausea, vomiting

What you can do

Small tumors may go away without treatment. Your doctor can do an ultrasound or other imaging scans to see if your tumor has receded. Larger tumors may need to be removed with surgery.

The first sign of ovarian cancer is often swelling in the ovaries. However, this cancer is very rare. According to the American Cancer Society, about 22,000 women in the United States receive a diagnosis of ovarian cancer each year.

Ovarian cancer usually doesn’t cause any symptoms until it has spread.

Symptoms of late stage ovarian cancer include:

  • swollen belly
  • pain in the lower belly or pelvis
  • feeling full soon after you’ve eaten
  • abnormal discharge or bleeding from the vagina
  • sudden weight change, loss or gain
  • urgent or frequent need to urinate
  • fatigue
  • pain during sex
  • changes in your periods
  • nausea
  • swelling in the legs

What you can do

Treatment depends on the type and stage of ovarian cancer you have. Options include:

  • Surgery. During surgery, your doctor will remove as much of the tumor as possible. Some ovarian tumors are treated with a bilateral salpingo-oophorectomy. This removes both the ovaries and fallopian tubes. Depending on whether — and where — your cancer has spread, you might also have a hysterectomy to remove your uterus.
  • Chemotherapy. This treatment uses drugs to kill cancer cells all over your body. You might get this treatment after surgery to kill any cancer cells that were left behind.
  • Hormone therapy. This treatment blocks or lowers levels of hormones that ovarian cancer needs to grow.
  • Targeted therapy. This treatment targets blood vessels and other substances that help ovarian cancer grow.

The main treatments for ovarian cancer are surgery to remove the tumor and chemotherapy. Your doctor might recommend that you combine two or more treatments to have the best outcome.

Enlarged ovaries typically aren’t cause for concern. But if your symptoms don’t subside after a few days, see your doctor for diagnosis. Enlarged ovaries may be a sign of an underlying condition that requires medical treatment.

Also see your doctor if you begin experiencing:

  • abdominal pain and fullness
  • pain during sex
  • heavy bleeding
  • skipped periods
  • abnormal vaginal discharge

It’s worth reporting any new or concerning symptoms to your doctor, especially if there isn’t an obvious reason for them.