Generally, this form of birth control has relatively few side complications, although on a rare occasion, the device will push through the wall of the uterus, resulting in a uterine perforation. If this is left undiscovered, the IUD can move around and damage internal organs. Also, in the unlikely event that a woman becomes pregnant while using an IUD, she is more likely to miscarry, give birth prematurely, or have an ectopic pregnancy, which is a dangerous condition whereby a fertilized egg develops in a fallopian tube. To avoid a pregnancy, it's important for a woman to wash her hands, insert her finger into the vagina, and feel for the string between periods, thereby ensuring that the device has not moved. Intra-uterine devices are incredibly effective and very popular, however, they do NOT protect against sexually transmitted diseases. Talk to your doctor about the pros and cons of an IUD.