Using the birth control shot is easy. Just make sure you get your shots on time, about every 3 months.
When do I need to get the shot?
The shot (sometimes called Depo-Provera, the Depo shot, or DMPA) is only effective if you get a new shot every 12-13 weeks (every 3 months, or 4 times a year). The shot must be given to you by a doctor or a nurse, so you have to make an appointment and then remember to go to the appointment. It sounds easy, but things come up.
You can start using the birth control shot whenever you want. If you get your first birth control shot within the first 7 days after the start of your period, you're protected from pregnancy right away. If you get the shot within 7 days after a miscarriage or an abortion, you're also protected from pregnancy right away. If you get the shot within 3 weeks of having a baby (giving birth), you're also protected right away.
For all other times, you need to use another form of birth control (like condoms) for the first week after getting the shot for the first time. As long as you get your next shots on time, you won't need a backup method of birth control after that first week. But remember that it's still important to use condoms to protect yourself from STDs.
What if I forget to get my shots on time?
It depends on how late you are. You can get your follow-up shots as early as 10 weeks after your last shot, or as late as 15 weeks after your last shot. But, if you get your shot more than 15 weeks after your last shot, you'll need to use backup birth control, like a condom, for the first week after getting your shot.
If you had vaginal sex without using a condom more than 15 weeks after your last shot, you should think about using emergency contraception. You may also need to take a pregnancy test before getting your next shot. The best way to prevent pregnancy while using the shot is to be super careful that you get your follow-up shots on time.