LILETTA® is an intrauterine device (IUD) that has been found to be more than 99% effective at preventing pregnancy for up to 6 years. When inserted into the uterus, LILETTA® slowly releases 52 mg of a progestin hormone called levonorgestrel. This is the same kind of hormone that is often used in birth control pills. Only a small amount of levonorgestrel enters your bloodstream. LILETTA® does not contain estrogen.