Ovarian cysts are sacs filled with fluid or semisolid material that form on or within one or both ovaries. Most ovarian cysts are harmless and go away on their own eventually, but some can cause serious symptoms. The causes of ovarian cysts include:

• Functional cysts: These are the most common type of ovarian cyst and occur as a result of ovulation, which is the release of an egg from the ovary. Functional cysts are linked to the menstrual cycle and are very common. They usually disappear in a few months without needing any treatment.

• Pathological cysts: These are caused by abnormal cell growth and are not related to the menstrual cycle. They can develop before and after menopause and can sometimes burst, twist, or grow very large and block the blood supply to the ovaries. Pathological cysts are usually non-cancerous, but a small number are cancerous (malignant) and often surgically removed.

• Endometriomas: These are cysts that form as a result of endometriosis, which is a condition where tissue similar to the lining of the uterus grows in other places, such as the ovaries and fallopian tubes.

• Dermoids: These are cysts that come from cells present from birth and do not usually cause symptoms.

• Cystadenomas: These are cysts that are filled with watery fluid and can sometimes grow large.

• Hormonal problems: These include taking a fertility drug that causes ovulation, for example, clomiphene or letrozole (Femara) .

• Pregnancy: Sometimes, the follicle that forms when you ovulate stays on your ovary throughout pregnancy. It can sometimes grow larger.

• Severe pelvic infection: If the infection spreads to the ovaries, it can cause cysts.

• Previous ovarian cysts: If youve had one ovarian cyst, youre likely to develop more.

Most ovarian cysts do not affect a womans chances of getting pregnant. However, some conditions that cause ovarian cysts, such as endometriosis and polycystic ovary syndrome (PCOS), can make it harder to get pregnant.