Depo-Provera is an injectable hormone-based contraceptive. It was approved by the U. S. Food and Drug Administration (FDA) in 1992. Lunelle, another injected contra­ceptive, was approved in 2000.

How Injected Contraceptives Work

The active ingredient in Depo-Provera is progestin, which inhibits the secretion of gonadotropins and prevents follicular maturation and ovulation. These actions also cause the endometrial lining of the uterus to thin, preventing implantation of a fer­tilized egg. Progestin also alters the cervical mucus. Lunelle combines progestin and estrogen, as do combination pills.

How to Use Injected Contraceptives

A health-care provider gives the Depo-Provera shot once every 12 weeks, ideally within 5 days of the beginning of menstruation. It usually takes 10 months after stop­ping Depo-Provera for a woman to get pregnant (Galewitz, 2000). Lunelle requires a monthly injection, and fertility returns immediately after stopping injections.