That stands for intrauterine device. It's placed inside a woman's uterus. The nonhormonal copper IUD, ParaGard, works for as long as 10 years. The hormonal IUDs must be replaced after 3-5 years. Both types make it harder for sperm to fertilize the egg. Fewer than 8 in 1,000 women get pregnant.
Pros: Long-lasting, low-maintenance. Hormonal IUDs can make periods shorter and lighter.
Cons: Irregular or heavier periods. Copper IUDs can make periods more painful. More expensive up front, may slip out, may cause side effects.