Gynecologic Conditions

Ovarian Cysts: Symptoms, Types and When They Need Treatment

By the Find Her Doctor editorial team · Updated November 1, 2026 · 5 min read

An ovarian cyst is a fluid-filled sac on or in an ovary. Most are harmless "functional" cysts that form during a normal menstrual cycle and disappear on their own without treatment. Some cause pain, bloating or pressure, and a small number need surgery, mainly when they're large, don't go away, or twist or rupture.

Lots of people find out about a cyst by accident: an ultrasound for something else, then a line in the report that says "4 cm left ovarian cyst," and a weekend of worried googling before anyone calls back. If that's you, start here.

First: what your ultrasound report is saying

A transvaginal ultrasound is the main test for cysts. It shows the size and what's inside. A few words carry most of the meaning:

• Simple: just fluid, thin smooth walls. This is the reassuring kind.
• Complex: has solid areas, thick walls or internal divisions. Many complex cysts are still benign (a bleeding functional cyst often looks complex), but they need a closer look.
• Hemorrhagic: a functional cyst that bled inside. Often looks complex, and typically resolves.
• Size in cm: larger cysts are more likely to cause symptoms or twist.

Ask your clinician to walk you through the report line by line. That's a completely normal request.

Symptoms, if any

Many cysts cause nothing at all. When they do:

• Pelvic pain, dull or sharp, usually on one side
• Bloating or fullness in the lower belly
• Pressure on the bladder or bowel, so you pee more often or get constipated
• Pain during sex, often deep and one-sided
• Period changes, like irregular bleeding

Bigger cysts are more likely to cause symptoms.

The types

Functional cysts (by far the most common)

These form as part of ovulation:

• Follicular cysts form when the follicle that normally releases an egg doesn't open and keeps growing.
• Corpus luteum cysts form after the egg is released, when the leftover follicle fills with fluid or blood.

They aren't a disease. They usually shrink without treatment within a few cycles.

Other cysts

• Dermoid cysts (mature teratomas) contain tissue like hair, skin or fat. Yes, really, and yes, people are always a little horrified. They're almost always benign but don't go away on their own.
• Endometriomas are filled with old blood and form when endometriosis grows on the ovary. Sometimes called "chocolate cysts." See our endometriosis guide.
• Cystadenomas grow from the surface of the ovary and can get large. Usually benign.
• Hemorrhagic cysts are functional cysts that bled inside, as above.

What about PCOS?

PCOS (polycystic ovary syndrome) is something different. The "cysts" in PCOS are many small follicles, not one larger cyst. See PCOS symptoms and diagnosis.

Other tests you might get

• Pelvic exam, to feel for a mass near the uterus
• Pregnancy test, to rule out pregnancy, including ectopic pregnancy, which can cause similar pain
• CA-125 blood test, sometimes, mainly after menopause or when a cyst looks concerning. CA-125 also rises with common benign conditions (periods, fibroids, endometriosis), so it's never used alone to diagnose cancer.

What happens next

"Watchful waiting" isn't doing nothing

For many simple cysts in people who still have periods, ACOG supports monitoring with a follow-up ultrasound instead of surgery. The repeat scan is often timed to a different point in your cycle, so the functional cyst has had a chance to resolve. Put the date on your calendar before you leave the office, and know which symptoms mean you shouldn't wait.

When surgery comes up

Surgery may be recommended if a cyst:

• Is large or keeps growing
• Doesn't go away after several cycles
• Looks complex or concerning on ultrasound
• Causes ongoing symptoms
• Twists the ovary (torsion)

Most cyst surgery is laparoscopic, through small incisions, and many people go home the same day. When possible, surgeons remove only the cyst (cystectomy) and keep the ovary. Sometimes the whole ovary has to come out (oophorectomy). More in what to expect from laparoscopy.

Rupture and torsion: the emergencies

Rupture. A cyst can burst, sometimes during sex or exercise. Many ruptures cause short-lived pain that settles on its own, but some cause internal bleeding.

Torsion. A large cyst can make the ovary twist on itself and cut off its blood supply. That's an emergency, because the ovary can be damaged if it isn't untwisted quickly. The pain is usually sudden and severe, often with nausea or vomiting.

Go to an emergency department or call 911 if you have:

• Sudden, severe pelvic or belly pain
• Pain with fever or vomiting
• Dizziness, weakness or fainting
• Cold, clammy skin or rapid breathing

Don't take a train or bus across town to your regular gynecologist's office for this. Go to the nearest emergency room.

After menopause

Functional cysts shouldn't form after menopause because ovulation has stopped. Simple cysts can still show up and are often benign, but any cyst found after menopause needs evaluation and follow-up. Your clinician may order repeat imaging and a CA-125 and may refer you to a gynecologic oncologist if the cyst has concerning features.

Fertility and prevention

Functional cysts don't affect fertility. Endometriomas and PCOS can be linked to fertility challenges. If you need surgery and want to get pregnant later, ask your surgeon how they'll protect your ovarian tissue.

Most functional cysts can't be prevented, since they're a normal part of ovulation. If you keep getting painful ones, hormonal birth control that stops ovulation may lower the chance of new ones. It won't shrink one you already have. Dermoids and cystadenomas aren't linked to anything you did.

Questions to ask your doctor

• What type of cyst do you think this is?
• Is it simple or complex?
• When should I have a follow-up ultrasound?
• Which symptoms should send me to the emergency room?
• If I need surgery, can you remove just the cyst and keep my ovary?
• Do I need any blood tests, like CA-125?

When to see a doctor

Make an appointment with a gynecologist if you have:

• Pelvic pain that lasts more than a few days or keeps returning
• Ongoing bloating, fullness, or feeling full quickly when you eat
• Pain during sex
• Changes in your periods
• A cyst found on imaging that needs follow-up

Get emergency care for sudden, severe pain or pain with fever, vomiting or fainting.

Finding a gynecologist in New York

Most ovarian cysts can be evaluated and followed by a general gynecologist, and many practices have ultrasound on site, which saves a separate trip. Browse gynecologists or use our provider search to find one in the five boroughs, Long Island or the Hudson Valley.

Frequently asked questions

Sources

• ACOG — Ovarian Cysts (Patient FAQ)
• ACOG — Evaluation and Management of Adnexal Masses (Practice Bulletin 174)
• MedlinePlus — Ovarian Cysts
• NIH, Office on Women's Health — Ovarian cysts

This article is for general education and is not medical advice. It does not replace an evaluation by a licensed clinician who knows your history. If you think you have a medical emergency, call 911.