A device usually made of plastic or metal, inserted into the uterus to prevent conception. IUCD can be a coil, loop, triangle, or T in shape; its material can be impregnated with a pharmaceutical agent. The primary action of all IUCDs is the induction of a foreign-body reaction within the endometrium. This sterile inflammatory process is toxic to gametes, primarily spermatozoa, and effectively prevents viable sperm from passing into the fallopian tubes. The copper-bearing device has an independent toxic effect on spermatozoa. The progestin-releasing devices produce changes in endometrial architecture and function that reduce the potential for implantation of a fertilized egg. The progestin effect on the cervical mucus also reduces the penetrability of sperm.

A small, plastic T-shaped device that is placed inside the uterus (the small, hollow, pear-shaped organ in a woman's pelvis in which a fetus develops) to prevent pregnancy. Intrauterine devices prevent sperm from fertilizing an egg, and prevent fertilized eggs from implanting in the uterus. The use of intrauterine devices is also being studied in the prevention and treatment of endometrial cancer and other conditions.

An Intra Uterine Contraceptive Device is a form of birth control that involves an object placed in the uterus to prevent fertilization of the egg by sperm. An IUCD can be a coil, loop, triangle, or T in shape; its material can be impregnated with a pharmaceutical agent.

Contraceptive devices placed high in the uterine fundus.

In the US, 12% of women who use contraception use intrauterine devices (IUDs); IUDs are becoming more popular because of their advantages over oral contraceptives: IUDs are highly effective.