A contraceptive injection provides protection from pregnancy for two to three months.

The injection is usually given in your buttock by a trained person. It is not painful and only takes a few minutes. It can take up to seven days before the injection starts to work.

How good is the injection at preventing a pregnancy?

  • The injection works very well at preventing a pregnancy.

  • If 100 women used the injection for a year and carried on with their normal sex life, then only 1 of those women would fall pregnant during that period.

What are other good things about the injection?

  • You can take it straight after an abortion.

  • It can last up to either 2 or 3 months, depending on the injection. After each 2 or 3 month period you will need to have another injection.

  • It can help to reduce heavy periods.

  • It does not interrupt sex.

What else should you know?

  • If you decide you don’t want it any more, you will have to wait 2 or 3 months after you’ve had the injection for its effects to end. For some women it may take a few more months for fertility to return.

  • Unlike condoms, it does not protect you from sexually transmitted infections.

Day to day life with your injection

  • Your regular bleeding pattern may change while using the injection. For example, your periods may stop for a short while or your periods may be irregular for a few months. These changes are not serious and are short-term. Your health and long term fertility will be unaffected.

  • Your injection will continue to work even if your bleeding pattern changes.

Frequently asked questions

  1. Does the injection cause weight gain or a fever or bleeding into the stomach?
    Some women using the injection will gain a small amount of weight. Typically this will be 1-2kg per year. Other women using the injection may lose weight. The injection does not cause a fever or bleeding into the stomach.

  2. Can I still fall pregnant if I stop the injection?
    Yes. The injection will not permanently end your fertility. Some women do not return to their pre-injection fertile state immediately when they stop the injection. It can be a couple of months before periods start again.

  3. Do I have to have follow up injections at exactly the right time?
    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 around the right time. It will still be effective if you are a couple of weeks early or late for your repeat injection. But you should not skip injections completely.

Find out about other short term contraceptive methods

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Compare different contraceptive methods, and see how well they work at preventing pregnancy.

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