Contraceptive Injection (Depo)

  • 96 – 99.8% Effective
  • No STI Protection
  • 12 weeks

What is the contraceptive injection (Depo)?

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

Fpv Contraceptive Injection Syringe
Photo of contraceptive injection vile and needle

How effective is the injection?

Each injection is more than 99% effective at preventing pregnancy and lasts for 12 – 14 weeks. If you have a late injection, it might only be 96% effective.

How does the injection work?

The 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 sperm from entering.

Illustration of mucus in cervix

How do I use the 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

When does it start to be effective?

When Depo is first injected, or after a break, it can take up to 7 days to start working to prevent pregnancy. This depends on the timing of your menstrual cycle and if you are already using contraception. Speak with your doctor, nurse or pharmacist for more information.

Where can I get the injection?

Your doctor or nurse will provide a script which you can take to the pharmacy, who will sell you the Depo. You will need to return to the clinic to have the Depo injected. It will be cheaper if you have a healthcare card.

What stops the injection from working?

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

What is good about the injection?

  • It is very effective.
  • It lasts for 12 – 14 weeks.
  • Most users have no vaginal bleeding (period) at all or very light bleeding.
  • Periods may be less painful.
  • You can use it while breast feeding.
  • No medications stop it from working.
  • It is another contraceptive option if you have difficulty taking the hormone oestrogen. The Pill (combined pill or oral contraceptive pill) and vaginal ring (NuvaRing) contains oestrogen and progestogen. The injection only contains progestogen.

Are there any side effects from using the injection?

  • Your vaginal bleeding pattern (period) will change. It might be more often and/or irregular (at odd times). Around 50 – 60% of people using the injection will have no bleeding at all (this is not harmful to the body). Frequent or prolonged bleeding may get better with time. Some medications can help with this bleeding, speak to your doctor or nurse for more information.
  • 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 for most people, as your bone density returns once you stop the injections.

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

  • headaches
  • changes to your skin
  • sore/ tender breasts
  • mood changes.

These side effects often settle with time.

Can the injection cause any serious health problems?

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

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

  • It is difficult to see a doctor or nurse every 12 – 14 to have the injection.
  • You have plans to become pregnant in the near future.
  • Have breast cancer or have been treated for breast cancer.
  • Have severe liver disease.
  • Have a number of risk factors for heart disease (e.g. smoking, diabetes).
  • Had a previous heart attack or a stroke.

What if I am late having the injection?

If you do not want to become pregnant and it is more than 14 weeks since your last injection, you can abstain from sex or use condoms until you can have your next injection. It can take up to 7 days for Depo to start working to prevent pregnancy.

During this time, you can continue to abstain from sex or use condoms. If you have unprotected sex in the time when your Depo is late or not effective, you might need emergency contraception.

What happens if I get pregnant while I am using the injection?

The injection is not known to harm a pregnancy. It is safe to continue the pregnancy or to have an abortion.

Can I use the injection after I have had a baby?

Generally, the injection can be administered straight after you give birth, even if you are breastfeeding. Speak to your doctor or nurse for more information.

What if I am using the injection and I want to become pregnant?

You can stop the injection at any time. It may take several months for your fertility to return.

What else should I know about the injection?

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Last updated: 28 May 2021