Healthdirect Free Australian health advice you can count on.

Medical problem? Call 1800 022 222. If you need urgent medical help, call triple zero immediately

healthdirect Australia is a free service where you can talk to a nurse or doctor who can help you know what to do.

beginning of content

Contraceptive injection

3-minute read

What is the contraceptive injection?

The contraceptive injection prevents pregnancy by injecting a synthetic version of the hormone progestogen, called Depot medroxyprogesterone acetate, or DMPA. The injection is also called Depo.

Depo prevents the body from producing its own hormones and releasing eggs from the ovaries. This is also how the contraceptive pill works.

The injection thickens the fluid at the entrance to the uterus (womb), which stops sperm from entering. It also thins the lining of the uterus, making it difficult for a fertilised egg to attach and develop.

It is given as an intramuscular injection into the buttock or the upper arm, and over the next 12 weeks the DMPA is slowly released into the bloodstream. To prevent pregnancy, an injection must be given every 12 weeks.

The injection is usually given during the first 5 days of the menstrual cycle, so it can start working straight away. If you have the injection at some other time in your cycle, it can take up to 7 days to start working.

Types of contraceptive injection

There are 2 birth control injections available in Australia:

How well does the contraceptive injection work?

The contraceptive injection is fairly effective if given every 3 months. If 100 women were to use it for 1 year, however, between 1 and 6 are still likely to become pregnant.

The contraceptive injection does not protect you against sexually-transmitted infections (STIs). You should use condoms for additional protection against STIs, although even condoms won't protect you from every type of infection.

Advantages and disadvantages of the contraceptive injection

The main advantages:

  • It is highly effective.
  • It can be used by women who can’t take oestrogen.
  • You only need to have the injection once every 3 months.
  • It is safe for use by most women, including those who are breastfeeding.
  • It usually stops menstrual bleeding, so is useful for women who have heavy periods or period pain.
  • Depo Provera may reduce the risk of ovarian cancer, endometrial (uterine) cancer, endometriosis and pelvic infection.
  • It can be used if you’re taking some medications that make the pill or implant less effective.

The main disadvantages:

  • It changes the pattern of the periods — they might become more frequent or longer lasting, then stop completely.
  • If you stop using it, it can take a while to get pregnant – it can take 18 months for fertility to return.
  • It can cause side effects such as weight gain, moodiness, decreased sex drive, headaches and acne.
  • It might cause bone thinning if used for a long time.
  • You have to visit a doctor every 3 months for an injection.

You shouldn’t have the injection if you are already pregnant, have a bleeding disorder, are taking anticoagulant medication, have had some types of cancer or other medical problems.

If you miss an injection, or stop having the injections

You need to have the injection every 12 weeks if you want to prevent pregnancy. It can be given up to 2 weeks late, but if you wait any longer than that, it's best to use condoms until the injection has had time to start working again.

When you stop getting the injection, it can take several months for your periods to return to normal, and even longer to become pregnant.

Resources and support

For more information, see Family Planning NSW.

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: January 2021


Back To Top

Need more information?

These trusted information partners have more on this topic.

Top results

Contraceptive Injection | Marie Stopes AU

Contraceptive injections are a form of contraception that involves an injection into a muscle of progestogen that prevent pregnancy for 12 weeks at a time

Read more on Marie Stopes Australia website

Contraceptive Injection | Family Planning NSW

The contraceptive injection is a hormone injection that prevents pregnancy. The injection works for 12 weeks. The injection contains depot medroxyprogesterone acetate (DMPA). DMPA is a hormone similar to progesterone. Progesterone is made naturally in the body by the ovaries.

Read more on Family Planning NSW website

Contraception - injections for women - Better Health Channel

betterhealth.vic.gov.au

Read more on Better Health Channel website

Injectable hormonal contraceptive

Depo Provera is a synthetic hormone (progestogen) that is given by injection every 3 months

Read more on WA Health website

Contraception

Contraception is the use of hormones, devices or surgery to prevent a woman from becoming pregnant. It allows couples to choose if and when they want to have a baby.

Read more on Pregnancy, Birth & Baby website

Contraception Options and Methods | Marie Stopes Australia

Modern contraception options and methods offer safe and effective ways of preventing pregnancy, helping couples plan their family. Marie Stopes contraception services specialise in the most effective methods at preventing unplanned pregnancy. Contact us today to discuss your options.

Read more on Marie Stopes Australia website

Contraception choices | Family Planning NSW

Contraception is necessary if you wish to avoid an unintended pregnancy. Several methods of contraception are available - check out this factsheet to find out more information.

Read more on Family Planning NSW website

Your guide to a no-regrets schoolies - Marie Stopes Australia

Want to make sure schoolies is the best week of your life? Make sure you check out this handy guide to help make your good times great!

Read more on Marie Stopes Australia website

Premenstrual Syndrome (PMS) | Family Planning NSW

Premenstrual syndrome (PMS), which is sometimes called premenstrual tension (PMT), refers to a range of physical and emotional symptoms that some women get in the second half of their menstrual cycle before their period starts.

Read more on Family Planning NSW website

Diet and medication while breastfeeding

Breastfeeding mothers don't need a special diet. But small amounts of what you consume can enter breast milk, so knowing what's safe is important. Learn more.

Read more on Pregnancy, Birth & Baby website

Healthdirect 24hr 7 days a week hotline

24 hour health advice you can count on

1800 022 222

Government Accredited with over 140 information partners

We are a government-funded service, providing quality, approved health information and advice

Australian Government, health department logo ACT Government logo New South Wales government, health department logo Northen Territory Government logo Government of South Australia, health department logo Tasmanian government logo Victorian government logo Government of Western Australia, health department logo