Ovarian cysts and the intrauterine device (IUD) are probably not related.

The IUD is a small plastic device that is placed in the cavity of the uterus to prevent pregnancy. It does not effect the development of eggs in the ovary and will not cause nor prevent the development of an ovarian cyst.

Every month a small number of eggs begin to develop in the ovary within a protective structure called the follicle. By the middle of the cycle, one egg becomes dominant. Its follicle will be about 2 cm in diameter. This egg is released from the ovary and has the potential to become fertilized. The other eggs degenerate within the ovary.

The follicle consists of the egg and a cluster of cells that surround it while it grows. The follicular cells produce fluid that nourishes the egg. Occasionally the amount of fluid that accumulates is excessive. The follicle becomes abnormally large and forms a cyst. When ovulation occurs, the cyst wall may bleed, resulting in a hemorrhagic cyst. Some women experience moderate pelvic pain during this process.