What is the depo-provera contraceptive injection effectiveness?

98%: The range of effectiveness for birth control depends on how precisely it is used. If you get the shot every three months as scheduled, the efficacy is 99%. The typical user efficacy is around 97%, which accounts for people getting their shot late. If you know you are going to miss a shot or be late, use a back up method until you are able to get the shot and talk to your doctor.