The contraceptive injection usually provides three months of contraceptive protection, depending on the type of contraceptive injection used. It works by slowly releasing a hormone called progestin which stops the body from producing an egg each month. The hormone also makes it harder for sperm to get into the uterus (womb).

There are two types of injections:

  • One (often called “Depo”) that needs to be given by a provider, usually in the buttock
  • A newer type with a smaller needle (called “Sayana Press”) that your provider can give you or you can give yourself at home in your belly or the front of your thigh
  • How good is the injection at preventing a pregnancy?
    • The injection works well at preventing pregnancy. However, its ability to stop a pregnancy largely depends on a person using it properly.
    • With typical use about 3 people out of 100 will become pregnant
    • If you think you will not be able to remember to have the injection once every 3 months, this may not be the right method for you
  • What are the advantages of the injection?
    • Depending on the type of injection it can last up to either two or three months. After this time you will need to have another injection.
    • The injection can help reduce heavy periods.
    • It is not used during sex so will not affect spontaneity
    • It is discreet – no one can see that you are using it
  • What are the disadvantages of the injection?
    • Once you have had the injection it cannot be removed. You will have to wait the two or three months for its effects to end, even if you decide you don’t want it anymore.
    • The injection can result in a delayed return to fertility of up to one year. After this your fertility will return to normal. However, if you wish to avoid pregnancy you must use another contraceptive method straight after stopping the injection
    • Your regular bleeding pattern may change while using the injection. In the first several months you may have irregular or prolonged bleeding. Over time your monthly bleeding may stop or become infrequent or irregular. This is not harmful and will return to normal after you stop using the injection.
    • Some users will gain a small amount of weight
    • Some users may experience headaches, acne, mood changes or abdominal bloating.
    • If you want to rely on the injections as a means of contraception then it is important that you attend for a follow up injection at the right time. If you are late for the injection, come as soon as you can and avoid sexual activity during this time or use condoms as a backup until you get your next injection.
    • Condoms are the only contraceptive method which protect against sexually transmitted infections. To ensure protection from both pregnancy and infection, we recommend "dual protection". This means using a male or female condom in addition to the contraceptive method of your choice to prevent pregnancy.
  • How do I use the injection?
    • You will need to see a health care provider to have Depo injections in your buttock once every three months
    • If you are using Sayana Press you may be able to be taught how to give these injections to yourself
    • Using Sayana Press at home involves giving yourself an injection with a small needle in your belly or the front of your thigh once every three months
    • You must have a reliable way of remembering when your next injection is due, e.g. by marking on your calendar or signing up for a text message reminder service
  • What are the possible risks of using the injection?
    • Using the injectable contraceptive may cause thinning of the bones. This isn’t normally a problem for most injection users as the bone replaces itself when you stop the injection and it doesn’t appear to cause any long-term problems.
    • As with any injection, there’s a small risk of a reaction at the spot the injection is given, which may cause irritation, swelling or a scar. This is slightly more common with Sayana Press than Depo