7.2 How copper-bearing IUCDs work
Copper-bearing IUCDs act primarily by stopping fertilisation. The copper slows down the movement of sperm within the woman’s uterus and so prevents them from reaching the fallopian tubes and fertilising the egg. The device also stimulates a strong reaction in the wall of the uterus, which prevents implantation of the egg (even if it is fertilised).
7.1 Types of IUCD
7.3 Effectiveness of IUCDs