Ovarian Cysts: Mostly Harmless Fluid Sacs That Usually Resolve on Their Own

01

What They Are

An ovarian cyst is a fluid-filled sac that forms on or inside an ovary. The most common type, a functional cyst, forms as a normal part of ovulation when a follicle doesn't release its egg or doesn't reabsorb fluid afterward, and these typically shrink and disappear within one to three menstrual cycles without any treatment.

Other, less common types include dermoid cysts and endometriomas, which form from different tissue and don't resolve on their own the way functional cysts do. Most ovarian cysts of any type cause no symptoms and are found incidentally on a pelvic ultrasound done for another reason.

02

When Cysts Cause Symptoms

When symptoms occur, they usually include dull pelvic pain or pressure on one side, bloating, or pain during sex. In anyone who could be pregnant, new one-sided pelvic pain should prompt a pregnancy test first, since an ectopic pregnancy causes similar pain and needs to be ruled out quickly.

Two different complications cause sudden, severe pain instead of a dull ache. A cyst can rupture, which can bleed into the abdomen. Separately, a cyst can make the ovary more likely to twist on its own supporting tissue — called ovarian torsion — which cuts off the ovary's blood supply. Both need emergency care, and torsion in particular needs treatment within hours to save the ovary.

Sudden, severe pelvic pain — especially with fever, vomiting, or fainting — is a different situation from the dull ache many cysts cause and should prompt an immediate trip to the emergency room rather than waiting to see if it passes.

03

How They're Evaluated

Pelvic ultrasound is the main tool for finding a cyst, measuring its size, and judging whether it looks like a typical fluid-filled functional cyst or has features that need closer follow-up, such as solid areas or irregular walls. Most cysts found this way are simply rechecked with a repeat ultrasound in six to twelve weeks to confirm they've resolved.

For cysts that persist, look complex on imaging, or appear after menopause — when functional cysts shouldn't be forming — a doctor may order a CA-125 blood test alongside imaging, since this marker is used as one piece of information when assessing the likelihood of an ovarian tumor, not as a stand-alone diagnosis.

04

Treatment Depends on the Type

Simple functional cysts usually just need watchful waiting with a follow-up scan. Hormonal birth control can reduce the chance of new functional cysts forming, though it doesn't shrink an existing one.

Cysts that are large, persistent, causing significant pain, or that show concerning features on imaging may be removed surgically, often with a technique that preserves the healthy ovarian tissue around them. The decision to operate weighs the cyst's size and appearance against the risks of surgery.

05

Living With a Diagnosis

Finding out about an ovarian cyst on a routine scan is common and, in the large majority of cases, not a cause for alarm. A gynecologist can explain what type of cyst was found and whether it needs a repeat scan, ongoing monitoring, or no further action.

Tracking any new or worsening pelvic pain, and seeking prompt care for sudden severe pain, is the main thing to watch for between checkups.