IUD means intrauterine device. It is a means of preventing pregnancy (a method of contraception). The IUD is a small object which the doctor or gynaecologist puts in the uterus. An IUD prevents a woman from getting pregnant for at least the next 3 years. If a woman had sexual intercourse without using an IUD or other contraception, an IUD may still prevent pregnancy if it is put into the woman's uterus up to 5 days after she has sexual intercourse.