The Intrauterine Device (IUD) is a T-shaped device implanted into the uterus for the purpose of contraception by preventing sperm from reaching the egg. There are four different IUDs available in the United States. Three of them, Liletta, Mirena, and Skyla, release a small amount of progestin similarly to a birth control pill, which usually makes periods lighter. One of them, ParaGard, also known as ‘the copper T IUD’, is hormone free and lasts longer than the hormonal options, but can cause heavier periods. IUDs are more than 99% effective, but they do not prevent against STIs.