What you describe sounds normal. Most girls/women get their first Depo-Provera® injection (shot) during the first five days of a normal menstrual period. You are then protected from pregnancy right after you get the shot. Other girls may get their first injection if they haven’t been sexually active for 2 weeks, used a condom every time they had sex or have a negative pregnancy test. You then need to use condoms at least 7 days after receiving the injection for additional protection. Call your health care provider and check if he/she thinks you need a pregnancy test.
Depo-Provera® can cause lighter menstrual periods or no period at all. If you get your Depo-Provera® injection at the right time, less than 1 woman will become pregnant in a year. Depo-Provera injections do NOT protect against sexually transmitted infections. You need to use a condom any time you have sex.