The Shot

What is the birth control shot?

  • The birth control shot is a hormone given by injection (a needle) that protects against pregnancy.
  • The injection must be received every three months.
  • The injection is usually given in the hip by a health care provider.

How does it work?

  • The birth control shot contains a hormone called progestin. This hormone stops your ovaries from releasing an egg cell each month. If there is no egg cell, you cannot get pregnant.
  • It makes the cervical mucous thicker. This makes it harder for sperm to get into the uterus.
  • It also changes the lining of the uterus so it is harder for a fertilized egg to stick to the uterus. Even if an egg is released and fertilized, it will not continue to grow.
  • The birth control shot prevents pregnancy 99.7% of the time.
  • Each injection gives you protection against pregnancy for about three months.

How soon does it start working?

  • When you have the birth control injection within the first five days of your menstrual cycle, it begins working 24 hours after the injection.
  • When you have the birth control injection after the first five days of your menstrual cycle, it begins working after 14 days.
  • When the birth control injection is given to a person immediately after they have given birth, or had a miscarriage or an abortion, it works immediately.

Where can I get the birth control shot?

  • You can get the birth control shot from your health care provider. If you need a regular health care provider, call the Family Doctor Finder at 204-786-7111.
  • Talk to your health care provider if cost is a problem for you.
  • If you’re under 22 you can get the birth control shot at teen clinics.

Does it protect me from STIs and HIV?

  • No. Using safer sex supplies every time you have sex reduces the risk of getting an STI (sexually transmitted infection) or HIV infection. Get tested regularly for STIs and HIV.

How often do I have the injection?

  • You have the injection once every three months.
  • You must remember to have the injection on schedule.
  • The birth control shot does not protect against pregnancy when you are late for your injection.

What if I forget or can’t come on time to get my three-month injection?

  • You must get your injection within 10-12 weeks of the last one. If you wait longer than 12 weeks, and have had sex that may result in pregnancy, you may be pregnant.
  • If you are having penis-vagina sex, you should consider another form of birth control such as condoms for 2 weeks after a late injection, to make sure you are protected against pregnancy during this time.

What if my health care provider doesn’t want me to stop taking it?

Every person receiving medical care has the right to make the final decision about their care. Your health care provider may suggest alternative methods, but they should never pressure you into any particular decision. If you find that your health care provider is not respecting your needs or rights, or if you feel uncomfortable with them, you have a right to pursue a different provider. Call the Family Doctor Finder at 204-786-7111 or 1-866-690-8260.

Will it make me sterile?

No. The effects of the birth control shot are temporary and the body should return to its natural fertility after about 9 months upon stopping the injections.

Are there side effects?

  • A loss of bone density is expected while on the birth control shot.
  • Some people using this method have bleeding between periods, heavy periods or no periods.
  • Other common side effects include breast tenderness, increased appetite, mood changes, headache or dizziness, and a decrease in sex drive.
  • You cannot stop the effects of the birth control shot immediately. The side effects are likely to last until the drug has totally worn off.
  • It takes an average of 9 months for your full natural fertility to return after you have stopped using the drug.

Studies have shown that females who have used the birth control shot for a long time have a slight decrease in the calcium in their bones. This can contribute to the development of a condition called osteoporosis. Exercise, enough calcium (1000 mg/day), and not smoking can help to prevent osteoporosis for all females.

Where can I get more information?

  • From your health care provider, community health centre, or public health nurse.If you need a regular health care provider, call the Family Doctor Finder at 204-786-7111.
  • From a teen clinic, if you are under 22 years old.
  • From the Facts of Life On-Line: e-mail your questions to

If you did not take the birth control shot on time and did not use another form of birth control method during sex, you can use emergency contraception from a pharmacy or community health centre.

SERC believes that all individuals have the right to access unbiased sexual and reproductive health information and services. They must also have the opportunity to explore their values and attitudes in making informed choices that are most appropriate for them, and have those choices respected and supported. SERC supports and defends a pregnant person’s right to choose parenting, adoption, or abortion.

Developed in collaboration with Klinic Community Health and Literacy Partners of Manitoba 2007
Sexuality Education Resource Centre 2016