Most ovarian cysts produce no symptoms at all, which is why many go undetected until an imaging scan picks them up for an unrelated reason. Ovarian cysts appear in roughly one in five women, and the vast majority are harmless, fluid-filled sacs that resolve on their own within weeks. Still, certain signs can tip you off that a cyst has grown large enough to cause problems, and knowing what to watch for can help you decide when it’s time to get checked.
Symptoms That Suggest a Cyst
Small cysts, typically under 5 centimeters, rarely cause any noticeable symptoms. Once a cyst grows larger, though, it can press on surrounding tissue and produce a recognizable pattern of discomfort. The most common sign is pelvic pain that comes and goes, usually felt as a dull ache or sharp twinge below your bellybutton, concentrated on one side. You might also notice a sense of fullness, pressure, or heaviness in your lower abdomen, along with bloating that doesn’t seem connected to what you’ve eaten.
Some people experience pain during sex, particularly with deep penetration, or feel an unusual pressure on their bladder that increases the urge to urinate. Menstrual cycles can also shift: periods may become heavier, lighter, or more irregular than usual. None of these symptoms are exclusive to ovarian cysts, which is part of what makes self-diagnosis unreliable. But if you’re noticing persistent one-sided pelvic pain paired with bloating or pressure, a cyst is a reasonable possibility worth investigating.
Types of Cysts and How They Behave
The most common ovarian cysts are functional, meaning they form as a normal part of your menstrual cycle. Follicular cysts develop when the small sac that releases an egg each month doesn’t open as expected and instead fills with clear fluid. These can grow as large as four inches but typically disappear within a few weeks without treatment.
Corpus luteum cysts form after ovulation. Once the egg is released, the leftover tissue normally produces progesterone to prepare the uterus for pregnancy. Sometimes that tissue seals shut and fills with fluid or blood. These cysts have a rich blood supply, which is why they can occasionally cause sharp pain if they leak or rupture. If no pregnancy occurs, they usually resolve within about two weeks, though some linger for a month or so.
Less common are dermoid cysts, which develop from egg cells and can contain unexpected tissue types like hair, teeth, or fat. These look distinctive on ultrasound and don’t go away on their own. They grow slowly and are almost always benign, but they typically need to be removed surgically because they won’t resolve like functional cysts do.
How Cysts Are Diagnosed
You can’t confirm an ovarian cyst based on symptoms alone. The standard diagnostic tool is a transvaginal ultrasound, a quick imaging scan that gives your doctor a clear view of the ovaries. On ultrasound, a cyst that appears thin-walled, smooth-bordered, and filled with clear fluid is almost certainly benign, with a malignancy rate of 0 to 1 percent regardless of age. Cysts under 10 centimeters that fit this description are generally monitored rather than treated.
If a cyst looks more complex on imaging, with thick walls, irregular borders, or solid components, your doctor will want to evaluate it more aggressively. In some cases, a blood test measuring a protein called CA-125 may be ordered, particularly for postmenopausal women or those with a family history of ovarian cancer. This test has significant limitations, though. Elevated CA-125 levels can be caused by endometriosis, uterine fibroids, liver disease, pelvic inflammatory disease, menstruation, and even pregnancy. It’s not accurate enough to serve as a general screening tool, and a normal result doesn’t rule out cancer entirely.
When Size Determines Next Steps
Size plays a major role in how a cyst is managed. Cysts under 5 centimeters across are generally considered benign and are left alone, especially in premenopausal women. Your doctor may recommend a follow-up ultrasound in six to eight weeks to confirm the cyst is shrinking or gone. Most functional cysts resolve within one to three menstrual cycles.
Cysts over 5 centimeters raise more concern and are more likely to be evaluated with additional imaging or surgery. Larger cysts carry a higher risk of rupture or torsion (twisting of the ovary), both of which can become emergencies. They’re also more likely to cause persistent symptoms simply because of the space they occupy in the pelvis.
Simple cysts are fairly common even after menopause. In one large study, simple cysts appeared in 14% of postmenopausal women at their first screening, and 8% developed new cysts each year. Most of those cysts stayed stable or resolved by the next annual exam, which is reassuring. But any new ovarian mass after menopause warrants careful evaluation because the baseline risk of malignancy is higher in that age group.
Red Flags That Need Immediate Attention
Most cysts are harmless, but two complications require emergency care: rupture and torsion. A ruptured cyst can cause sudden, severe pain on one side of your pelvis. If the cyst had a significant blood supply (as corpus luteum cysts do), the rupture can cause internal bleeding, leading to faintness, dizziness, rapid breathing, or cold and clammy skin. These are signs of shock and need immediate treatment.
Ovarian torsion happens when a cyst makes the ovary heavy enough to twist on its own blood supply. The hallmark is sudden, intense pain accompanied by severe nausea and vomiting. This is a surgical emergency because the blood supply to the ovary can be cut off permanently if the twist isn’t corrected quickly. Fever alongside pelvic pain can signal infection, and heavy vaginal bleeding paired with any of these symptoms also warrants a trip to the emergency room.
Who Is More Likely to Develop Cysts
Any person with functioning ovaries can develop cysts, but certain factors increase the likelihood. Hormonal conditions like polycystic ovary syndrome (PCOS) cause multiple small cysts to form on the ovaries as part of the disease process. Endometriosis can lead to endometriomas, sometimes called “chocolate cysts,” which form when endometrial tissue grows on the ovary and creates a blood-filled pocket. Fertility medications that stimulate ovulation can also increase the chance of cyst formation, particularly large or multiple cysts, as a side effect of the hormonal stimulation.
If you’ve had one ovarian cyst, you’re more likely to develop another. Hormonal birth control that suppresses ovulation can reduce the risk of new functional cysts forming, though it won’t shrink cysts that already exist. Previous pelvic infections and a history of cysts in your family can also raise your risk profile.