Contraceptive coil. Nurse holding a hormonal intrauterine device (IUD, coil). An IUD is a small contraceptive device that is inserted into the uterus (womb) in order to prevent fertilisation. It can contain either copper or levonorgestrel (synthetic progestogen hormone, as here). Copper acts as a spermicide and copper IUDs primarily work by disrupting sperm mobility and damaging sperm so that they are prevented from joining with an egg. IUDs typically have a life of 5 years, after which they should be removed.