- 96 – 99.8% Effective
- No STI Protection
- 12 weeks
On this page
- What is the contraceptive injection (Depo)?
- How effective is the injection?
- How does the injection work?
- How do I use the injection?
- When does it start to be effective?
- Where can I get the injection?
- What stops the injection from working?
- What is good about the injection?
- Are there any side effects from using the injection?
- Can the injection cause any serious health problems?
- Reasons why the injection might not be a good option for you
- What if I am late having the injection?
- What happens if I get pregnant while I am using the injection?
- Can I use the injection after I have had a baby?
- What if I am using the injection and I want to become pregnant?
- What else should I know about the injection?
- Where to get more information and support
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.
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.
It also thickens the fluid around the cervix (opening to the uterus/womb). This helps to prevent sperm from entering.
How do I use the injection?
Depo is injected by a doctor or nurse into the arm or bottom muscle every 12-14 weeks.
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:
- 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.
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?
You might be interested in watching:
Where to get more information and support
- Sexual Health Victoria
- A doctor or nurse
- Your local community health service
- An obstetrician or gynaecologist
- 1800 My Options phone line 1800 696 784 or website
- Better Health Channel
- Equinox – for transgender services
- Jean Hailes
- Marie Stopes Australia
- Multicultural Centre for Women’s Health
- The Women’s (The Royal Women’s Hospital)
If you are using the internet for information, only use reliable and reputable websites, such as the ones provided above.