It’s important to stay on a schedule with getting your Depo Provera shot. If you get your birth control shot later than scheduled, you might not be fully protected against pregnancy, especially if it’s more than 15 weeks since your last shot. In that case, use a backup method like condoms for the first week after getting your shot. If you have unprotected sex after 15 weeks without a shot, consider emergency contraception and possibly a pregnancy test before your next shot. To best prevent pregnancy, always get your shot on time.