Using the Birth Control Shot PDF

What is the Birth Control Shot?

The Birth Control Shot is an injectable long-acting birth control, which contains the hormone progestin. It is given by injection and repeated approximately every 3 months. It prevents pregnancy by thickening the cervical fluid to keep sperm from reaching an egg, and also may reduce the chances of releasing an egg (ovulation) in some users.

How effective is the Birth Control Shot?

The shot is a very effective method of birth control. The shot is about 96% effective at preventing pregnancy in typical use, which means that around 4 out of 100 people using it as their only form of birth control will get pregnant in one year. With consistent and correct use it can be over 99% effective.

How do I get the Birth Control Shot?

Talk with a healthcare provider about whether the shot is right for you. You will need to visit a clinic every 11-14 weeks to get the birth control shot.

  • Lighter or no periods (which is safe), over time most people stop bleeding completely 
  • Improved menstrual symptoms for some users (such as cramps). 
  • The shot is private/discreet (there are no signs that you are using this method)
  • You only need to remember to get the shot every 3 months. 
  • You have complete control over the method and no one can interfere with its effectiveness.
  • May possibly treat and decrease pain associated with endometriosis
  • Reduced risk of uterine cancer and ovarian cancer.
  • A good choice for people who cannot use estrogen.
  • Unpredictable bleeding is common. especially during the first year of use, including spotting, prolonged bleeding or no bleeding. This often improves over time.  
  • You need to plan ahead to return every 11-14 weeks for injections
  • Side effects may include weight gain, headaches, breast tenderness and mood changes. 
  • Side effects from the shot may continue for 6 or more months after you have stopped using it  
  • When you stop using the shot, there may be a delay in return to fertility (on average 9 months), but some people get pregnant right away
  • The shot does not protect against sexually transmitted infections (STIs).

When do I start the Shot? 

It is recommended you get the shot right away. The shot is effective in preventing pregnancy after one week of use, so you need to use a backup method of birth control such as condoms or not have sex for 7 days. You do not have to wait for your period, but if you happen to get your shot within the first 5 days of your period you are protected right away.

What if I am late for my injection?

If it is less than 15 weeks since your last injection
  • Get your next shot as soon as possible
  • You will still be protected from pregnancy as long as you receive another dose before the end of 15 weeks 
If it has been more than 15 weeks since your last injection
  • Get your next shot as soon as possible
  • You may not be protected from pregnancy. To reduce the chance of getting pregnant:
    • Use a backup method such as condoms or do not have sex until 7 days after your next shot
    • Consider using emergency contraception if you had sex without a condom in the last 5 – 7 days. For information on emergency contraception, please see our website at:

Seek medical attention immediately if you have any of the following symptoms, as they could indicate a serious complication:

  • Signs of pregnancy
  • Heavy bleeding
  • Depression
  • Severe,  lower abdominal pain (may be a sign of pregnancy)
  • Pus, prolonged pain, redness, itching or bleeding at the injection site (may be a sign of infection).

The shot may have an effect on bone density, but this is reversible. If you have concerns about your bone density talk to your health care provider. 

Some medications and over-the counter herbal supplements (such as St. John’s Wort) may interact with or decrease the effectiveness of birth control. Be sure to mention that you are using birth control to your health care provider or pharmacist.

Questions? We’re here for you!

We know it can be confusing to choose a method. We are here to help. Our Options for Sexual Health Clinicsare staffed by health care professionals who are there to answer your questions about sex, sexuality, and sexual health.  They can help you learn how to use the method you choose and bring you back to check in on how the method is working for you.

Between visits or anytime you have questions about sex, sexuality, or sexual health, our Sex Sense team is there to answer your questions Monday-Friday 9 a.m.- 9 p.m. (PST) by phone (1-800-739-7367) or by email at

This is general information and should not be used in place of individual consultation with a qualified healthcare provider.

Have a question about sexual health?