An intrauterine device (IUD) is a method of birth control that is placed inside the uterus 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 anywhere from 3 to 12 years, depending on the type). Talk to your doctor about how long you can use it.

The IUD is very effective at preventing pregnancy.