Ovarian cysts explained: causes, symptoms and care

What ovarian cysts are

The ovaries are two small organs, one on each side of the womb, that store eggs and make hormones. An ovarian cyst is a fluid-filled sac that develops on or inside an ovary. They are extremely common, especially in women who are still having periods. Most are what doctors call functional cysts, meaning they form as a normal part of the monthly cycle when a follicle that would release an egg fills with fluid instead of bursting, or seals over afterwards. These functional cysts are harmless and usually disappear on their own within a few months. Other, less common types exist too, but the great majority of cysts found in younger women are of this ordinary, temporary kind.

Symptoms to watch for

Most ovarian cysts cause no symptoms and are found by chance during a scan done for another reason. When symptoms do occur, they can include pain or a dull ache low down in the tummy or pelvis, bloating or a feeling of fullness, and sometimes discomfort during sex. A larger cyst may cause a sense of pressure, or the need to pass urine more often if it presses on the bladder. Occasionally cysts affect periods, making them irregular, heavier or lighter. These symptoms are common to many conditions, so they do not necessarily mean a cyst or anything serious. Still, new or persistent pelvic pain, bloating or changes in your periods are worth discussing with your GP.

When a cyst needs urgent attention

Although most cysts are harmless, two complications can cause sudden, severe symptoms. A cyst can twist the ovary (called torsion), cutting off its blood supply, or it can burst. Both can cause sudden, severe one-sided tummy pain, sometimes with feeling sick, vomiting or a fast heartbeat. Sudden severe pelvic pain, especially with dizziness, faintness or fever, needs urgent medical assessment, so contact NHS 111 or go to A&E, and call 999 if you feel very unwell or collapse. It is also important to know that severe one-sided pain in someone who could be pregnant may be an ectopic pregnancy, another emergency. Because these situations overlap, sudden severe pelvic pain should always be assessed promptly rather than waited out.

How cysts are checked and monitored

When a cyst is found or suspected, an ultrasound scan, often done internally through the vagina, gives the clearest picture of its size and whether it looks simple, meaning fluid-filled and harmless-looking, or more complex. In some women, particularly after the menopause or where a cyst looks unusual, a blood test may be done as one piece of information among several. Many simple cysts need no treatment at all and are simply rechecked with a repeat scan after a few weeks or months to confirm they have gone or stayed stable. This watchful approach avoids unnecessary treatment, since so many cysts resolve by themselves. Your care depends on your age, symptoms and how the cyst looks on the scan.

Treatment and reassurance

Because most cysts disappear on their own, treatment is often not needed. When it is — for a cyst that is large, causing symptoms, not going away, or looking unusual — an operation, usually keyhole surgery, may be used to remove the cyst while preserving the ovary where possible. After the menopause, cysts are watched a little more carefully because the small chance of a cyst being something more serious rises with age, though even then most are still benign. Conditions such as polycystic ovary syndrome and endometriosis are different from ordinary cysts and are managed in their own way. The overall message is reassuring: ovarian cysts are common, usually harmless, and most need only monitoring or no treatment at all.