Ovarian cysts

An ovarian cyst is a fluid-filled sac on or inside an ovary. Most are harmless, and many disappear without treatment. Finding one does not automatically mean surgery is needed: the next step depends on its appearance, your symptoms and whether you have been through menopause.

Functional cysts and other types

The most common cysts are called functional cysts because they form as part of the menstrual cycle. A follicle is a small sac in which an egg develops. If it does not open to release the egg, fluid can remain and form a follicular cyst. A corpus luteum cyst forms after an egg has been released.

Other types form in different ways. Endometriomas are linked to endometriosis. Dermoid cysts develop from cells present from birth, while cystadenomas can contain watery fluid and grow large. Ask which type your clinician suspects and how that affects the follow-up plan. The word “cyst” covers several different types.

A functional cyst is different from polycystic ovary syndrome, commonly called PCOS. Cysts linked to the menstrual cycle are separate from hormone-related conditions such as PCOS. If you have been told about both, ask your clinician to explain each finding.

What symptoms can lead to a scan

Many cysts cause no symptoms. Others cause pelvic discomfort, bloating, pain during sex or pressure affecting the bowel or bladder. Book a medical appointment for persistent bloating, feeling full quickly or pain that keeps returning. These symptoms have several possible explanations, so a clinician needs to assess them.

Ultrasound helps show a cyst’s size, location and whether it contains fluid or solid areas. A scan may involve a probe placed inside the vagina. Depending on the assessment, a clinician may also arrange blood tests or a pregnancy test. Ask what each test can tell you and when you will hear the results.

Monitoring and treatment

Monitoring may involve another ultrasound to see whether the cyst has gone or changed. Surgery is more likely to be discussed if a cyst persists, grows, causes symptoms or has features that need closer investigation. After menopause, there is a higher risk of a cyst being cancerous, and the assessment takes this into account. Most ovarian cysts are not cancer.

The contraceptive pill may be offered to reduce the chance of new functional cysts if they keep happening. It does not shrink an existing cyst. Your pharmacist, GP or doctor can advise about the available options, pain relief and suitability. Follow medicine leaflets and any prescription instructions.

If surgery is recommended, ask whether the plan is to remove the cyst alone or whether an ovary may also need to be removed. Most cysts do not affect the chance of pregnancy, but the underlying condition and the proposed operation can matter. Discuss whether you want a future pregnancy before agreeing to surgery, even if you are not planning one now.

Pain that needs help now

A cyst can rupture, meaning it breaks open, or an ovary can twist, which is called torsion. Twisting can interfere with the ovary’s blood supply. Sudden severe pelvic pain, often with nausea or vomiting, can be a sign of these complications. A ruptured cyst can sometimes cause internal bleeding.

Call 999 now (UK) or 911 (US), or your local emergency number, for severe or worsening pelvic pain, or pelvic pain with faintness, difficulty breathing or heavy vaginal bleeding. Do not wait for a follow-up scan or assume the pain is from a cyst already being monitored.

Get help today from NHS 111 or an urgent GP service (UK), or your doctor or urgent care service (US or elsewhere), for abdominal pain with nausea or vomiting, or for pelvic pain if you are pregnant or could be pregnant, or if pelvic pain comes with a very high temperature or feeling hot, cold or shivery. Use emergency care if pain is severe or you feel faint. The NHS cyst page directs sudden severe pain to urgent assessment; its broader pelvic-pain guidance directs severe pain to emergency care. Follow the emergency route for severe symptoms.

Book a GP appointment (UK), or see your doctor (US or elsewhere), for ongoing pelvic pain, persistent bloating or feeling full quickly. At a follow-up appointment, ask what changes need an earlier call and who to contact between scans.