What are ovarian cysts? Ovarian cysts are fluid-filled sacs which develop in the ovaries and are very common before the menopause. They are usually diagnosed by an ultrasound scan and sometimes also by blood tests. Symptoms can include those associated with ovarian cancer which we list here. If an ovarian cyst is not causing any problems, the cyst may be monitored for changes depending on its size, but otherwise not treated. Sometimes hormonal contraceptives are prescribed to stop cysts recurring. If the cyst is large, causing symptoms, or if there is a suspicion the cyst is cancerous, then it may be removed by surgery. Up to one in ten people may need surgery for an ovarian cyst at some time in their life. There are two main types of ovarian cysts: functional and pathological. . Functional ovarian cysts These include cysts which are linked to the menstrual cycle such as follicular cysts, corpus luteum cysts and haemorrhagic cysts. They are not cancerous and will usually resolve on their own within two or three menstrual cycles. . Pathological cysts These are abnormal growths and can develop before or after the menopause. They include endometriomas, dermoid cysts (teratomas), and cystadenomas. Most of these cysts will not be cancerous. Pathological cysts can sometimes burst or grow very large; a small number will be cancerous. In these circumstances the cyst, possibly the whole ovary, will probably need to be surgically removed. If a cyst bursts, it can cause sudden, severe pain. If the cyst causes your ovary to twist (torsion), you may have pain, nausea and vomiting. You may also experience faintness, dizziness, weakness and rapid breathing. If this occurs, you will need to go to your local emergency department. . After menopause If you are post-menopausal, the recommendation is that a risk of malignancy index (RMI) should be completed by your doctor or specialist to guide the management of the ovarian cysts. This will help identify your risk of ovarian cancer and whether you should be treated by a general gynaecologist or by cancer services. It uses a blood test to check for ovarian cancer called CA125 and the appearances at ultrasound scan to provide a combined score or likelihood that any cyst is cancerous. . Further information NHS information on ovarian cysts Royal College of Obstetricians and Gynaecologists patient information on ovarian cysts before the menopause Royal College of Obstetricians and Gynaecologists guidance on ovarian cysts in post menopausal women Royal College of Obstetricians and Gynaecologists guidance on ovarian masses in premenopausal women Polycystic ovary syndrome (PCOS) is different to ovarian cysts. You are not at higher risk of ovarian cancer if you have PCOS, but your risk of endometrial cancer is slightly increased. Verity is the UK PCOS self-help organisation, you can view their website here.