Iud - GCSE Biology Definition

An IUD, or intrauterine device, is a small, T-shaped plastic device that doctors place inside a woman's uterus to help prevent pregnancy. It’s a form of long-term birth control and works by stopping sperm from reaching and fertilising an egg. There are two main types of IUDs: one releases copper, which is toxic to sperm, and the other releases hormones to thicken the cervical mucus and stop ovulation. IUDs are very effective, can last for several years, and are a reversible form of contraception, which means a woman can have it removed when she wishes to become pregnant.