What is the cause of a ovarian cyst?

Common causes of ovarian cysts include:

* Hormonal imbalances. Ovarian cysts can develop as a result of hormonal imbalances that occur during a woman's menstrual cycle. For example, a condition called polycystic ovary syndrome (PCOS) is characterized by an imbalance of hormones that can lead to the formation of ovarian cysts.

* Pregnancy. Ovarian cysts can also develop during pregnancy. These cysts are called corpus luteum cysts and they usually disappear on their own after pregnancy.

* Endometriosis. Endometriosis is a condition in which tissue that normally lines the uterus grows outside of the uterus. Endometriosis can cause the formation of ovarian cysts.

* Pelvic inflammatory disease (PID). PID is an infection of the female reproductive organs. PID can cause the formation of ovarian cysts.

* Certain medications. Some medications, such as clomid, can cause the formation of ovarian cysts. Clomid is a medication that is used to treat infertility.