An intrauterine device (IUD) is a method of birth control that is placed inside the uterus to prevent pregnancy. Hormonal IUDs release a type of progestin to prevent pregnancy. Copper IUDs do not use hormones to prevent pregnancy.

All IUDs have a plastic string that extends through the opening of the cervix into the vagina. The string allows a health professional to remove the device at your request or at the end of its effectiveness (usually 5 to 10 years, depending on the type).

The IUD is very effective at preventing pregnancy.