Problemas de salud

Ovarian cysts

Revisado: 4 de octubre de 2026

Solo en inglés por ahora

Ovarian cysts are fluid-filled sacs on an ovary. Most are harmless and go away on their own, but a few need treatment and some signs need urgent help.

What ovarian cysts are

An ovarian cyst is a sac filled with fluid that forms in or on an ovary. They are very common, and most women have one at some point. The most common kind, called functional cysts, form as part of the menstrual cycle. Each month an egg grows inside a small sac (follicle). A cyst can form if the follicle does not open to release the egg, or if the sac does not shrink afterwards. These cysts are usually harmless and go away within a few months.

Other types of cyst

Less often, cysts form because cells grow in an unusual way. These are called pathological cysts. Some cysts are linked to conditions such as endometriosis. Most cysts are not cancer, but the risk of a cyst being cancer is higher after menopause. Polycystic ovary syndrome (PCOS, now also called PMOS) is a different condition. People with PCOS can have many small cysts, along with irregular periods and high levels of hormones such as testosterone.

Symptoms

Most ovarian cysts are small and cause no symptoms. You may only find out about one during an internal (pelvic) examination or a scan. A cyst usually causes symptoms only if it is very large, bursts (ruptures) or twists, which can block the blood supply to the ovary. Symptoms can include pelvic pain on the side of the cyst, a feeling of pressure, bloating or a swollen tummy, needing to pee often, pain during sex, and changes to your periods.

Tests and treatment

An ultrasound scan can show the size of a cyst and what it looks like, and you may have blood tests. Many cysts need no treatment. Your doctor may suggest waiting and having repeat scans to check whether the cyst has gone. Hormonal contraception that stops ovulation can help prevent new cysts. You may need an operation if the cyst is painful, stays for a long time, or you have been through menopause. This may be done through small cuts in the tummy (laparoscopy).

When to get help

See a doctor or nurse if you have symptoms such as pelvic pain, bloating, pain during sex or changes to your periods. Get emergency help straight away if you have sudden, severe pain in your tummy or pelvis. Also get emergency help if you have pain with a fever or vomiting, feel faint, dizzy or weak, or are breathing fast. These can be signs that a cyst has burst or twisted. If you could be pregnant, severe pain on one side needs emergency help too, as it can be a sign of an ectopic pregnancy.

This is general information, not a diagnosis. Sudden, severe pelvic pain always needs urgent medical help.