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.