What Causes Ovarian Cysts?
Eggs grow, develop, and mature in the ovaries and then are released during ovulation, part of the monthly menstrual cycle that occurs during the childbearing years. Ovarian cysts are fluid-filled sacs that form on the ovaries when the follicles (sacs) on the ovary that contain the egg mature, but do not release the egg into the fallopian tube where it would be fertilized.