Contraceptive Injection (Depo)

  • 96 – Over 99.5% Effective
  • No STI Protection
  • 12 weeks

What is the contraceptive injection?

The contraceptive injection (also called Depo), is an injection of the hormone progestogen. Progestogen is similar to the hormone produced by the ovaries. It is sold as Depo-Provera® or Depo-Ralovera® in Australia.

Fpv Contraceptive Injection Syringe
photo of contraceptive injection needle and vile

How effective is the contraceptive injection?

Each injection is more than 99.5% effective at preventing pregnancy and lasts for 12 -14 weeks. If you have a late injection it might only be 96% effective.

What stops the contraceptive injection from working?

The injection might not work if you are late having your injection.

How do I use the contraceptive injection?

Depo is injected by a doctor or nurse into the arm or bottom muscle every 12-14 weeks.

illustration of person receiving contraceptive injection

How does the contraceptive injection work?

The contraceptive injection works by preventing the ovaries from releasing an egg each month.

illustration of eggs not being released by ovaries

It also thickens the fluid around the cervix (opening to the uterus/womb). This helps to prevent the sperm from entering.  

illustration of mucus in cervix

When it is first injected or after a break it can take up to seven days to start working to prevent pregnancy.  

Where can I get the contraceptive injection?

Your doctor or nurse will write you a script and you can get the Depo from your pharmacy. You will need to return to the clinic to have the Depo injected. It will be cheaper if you have a healthcare card.

What is good about the contraceptive injection?

  • It is very effective
  • Most users have no vaginal bleeding at all or very light bleeding
  • Periods may be less painful
  • It lasts for 12-14 weeks
  • It can be used while breast feeding
  • No medications stop it from working; and
  • It is another choice if you have difficulty taking the hormone oestrogen. ‘The Pill’ (combined pill) and vaginal ring contains oestrogen and progestogen. Depo only contains progestogen.


Are there any side effects from using the contraceptive injection?

  • Your vaginal bleeding pattern/period will change. It might be more often and/or irregular (at odd times). Around 50-60% of women will have no bleeding at all (this is not harmful to the body). Episodes of prolonged or frequent bleeding may get better with time. Some medications can help with this bleeding, speak to your doctor or nurse.
  • Around 20% of users will gain weight.
  • There is a small drop in your bone density (your bones become thinner). This is not thought to be harmful, as your bone density returns once you stop the injections.

Other possible side effects for a small number of users can include:

  • Headaches
  • Bloating
  • Changes to your skin
  • Sore/ tender breasts
  • Mood changes

These side effects often settle with time.

Can the contraceptive injection cause any serious health problems?

There are no known serious health risks from having the contraceptive injection.

Reasons why the contraceptive injection might not be a good option for you:

  • Have plans to become pregnant in the near future
  • Have been treated for breast cancer
  • Have severe liver disease
  • Have a number of risk factors for heart disease (e.g. smoking, diabetes)
  • Have previously had a heart attack or a stroke

What if I’m late having the contraceptive injection?

Once it is more than 14 weeks since your last injection, use condoms until you can have your next injection. Keep using condoms for another seven days.

What else should I know about the contraceptive injection?

  • The injection does not protect you from sexually transmissible infections (STIs).
  • It is good to write down the date or enter a reminder into your phone for when your next injection is due.
  • The contraceptive injection is one of many types of contraception. See other options.

You might be interested in watching:

Where to get more information, support or advice

This is general information only, you should speak to your doctor for advice and further instruction.

Last updated: 27 June 2018