Answer by
SqueakyFrancis (31)
Both copper and hormonal IUDs have very good effectiveness rates for preventing pregnancy. Copper IUDs may cause heavier periods or more severe cramping, whereas hormonal IUDs may lead to lighter or no periods, though neither is guaranteed, and most side-effects from copper go away in time. Copper IUDs are used for approximately 10 years,about twice as long as hormonal ones.