Birth Control Shot: What It Is and Who It Helps

One injection every three months can prevent pregnancy — that’s the idea behind the birth control shot. Known commonly as Depo-Provera or by its drug class DMPA, the shot contains a progestin that stops ovulation and thickens cervical mucus. If you struggle with daily pills or want a private method, the shot is worth considering.

How it works and the schedule

The standard schedule is one shot every 12 to 13 weeks. Some clinics use Depo-Provera (intramuscular) while others offer a subcutaneous version (smaller needle). You get the injection in the arm or butt. If you’re on time, the shot is over 99% effective. Miss an appointment by more than two weeks and effectiveness drops—use condoms until you’re back on schedule.

If you start the shot within the first five days of your period, you’re protected right away. If you start at another time, your provider will likely ask you to use a backup method for seven days. Fertility usually returns after you stop, but it can take several months. Many people get pregnant within a year, but some wait longer — plan accordingly if you want a quick return to fertility.

Pros, cons, and common side effects

Pros: no daily action, discreet, reliable when kept on schedule, may reduce heavy periods and cramps. It’s safe while breastfeeding and works well for people who can’t take estrogen.

Cons: irregular bleeding or spotting is common in the first months. Some people gain weight or notice mood changes. There’s a known link between longer use and small decreases in bone mineral density; this usually recovers after stopping, but your provider will weigh risks if you plan long-term use.

Other side effects can include headaches, acne changes, and injection site soreness. Serious risks are rare. If you have unexplained vaginal bleeding, active blood-clotting disorders, or are already pregnant, the shot is not appropriate. Always tell your clinician about existing health issues and medications.

Practical tips: set a calendar reminder for your next shot, bring insurance info or check local clinic sliding scales for cost, and ask about the type used (IM vs. subQ). If you’re late by less than two weeks, get the injection and use a condom for one week. If it’s been more than two weeks, take a pregnancy test and talk to your provider before getting a new shot.

Want to switch methods? You can get the shot while using other contraception, but discuss timing to avoid overlap or gaps. If you have bone health concerns or plan pregnancy soon, consider alternatives like IUDs or implants.

Talk with a clinician to get personalized advice. The birth control shot is simple and powerful for many people, but the trade-offs matter. Ask questions about timing, side effects, and how it fits with your life and future plans.