Contraceptive injection
5-minute read
Key facts
- The contraceptive injection is a type of contraception (birth control).
- The injection contains a hormone called depot medroxyprogesterone acetate (DMPA), which is like the hormone progesterone.
- To prevent pregnancy, birth control injections must be given every 3 months.
What is the contraceptive injection?
The contraceptive injection is a type of contraception (birth control).
The injection contains a hormone called depot medroxyprogesterone acetate (DMPA), which is like the hormone progesterone. It‘s also called simply ‘Depo’ or ‘birth control injection’.
The DMPA is slowly released into your bloodstream over 3 months. You need a new injection every 3 months to prevent pregnancy.
How does the contraceptive injection work?
The contraceptive injection prevents pregnancy by:
- preventing ovulation (eggs being released from your ovaries)
- thickening the mucus at the entrance to your uterus (womb) so sperm can't enter
How is the contraceptive injection given?
The birth control injection is given into your buttock or upper arm muscle. A doctor or nurse can give the injection. To prevent pregnancy, an injection must be given every 3 months.
If you want to get a prescription for the contraceptive injection:
- see your doctor
- visit Family Planning Australia (NSW only)
- visit Family Planning Alliance Australia (ACT, QLD, NT, SA, TAS, VIC and WA)
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There are 2 brands of birth control injections available in Australia:
Your doctor will discuss with you whether back-up contraception is needed for the first week after your injection.
How well does the contraceptive injection work to prevent pregnancy?
The contraceptive injection is very effective if given every 3 months.
With typical use, about 1 in 25 women using the contraceptive injection will get pregnant. This is low compared to some other contraceptive methods.
What are the advantages and disadvantages of the contraceptive injection?
Advantages of the birth control injection:
- It’s highly effective.
- You only need to have the injection once every 3 months.
- It can be used straight after having a baby and if you are breastfeeding.
- It usually stops your periods, so is useful if you have heavy periods or period pain.
Disadvantages of the birth control injection:
- It changes the pattern of your periods — they might become more frequent or longer lasting, then stop completely.
- It can take a while to get pregnant when you stop using injections — it can take 18 months for fertility to return.
- You may have side effects such as weight gain, headaches, mood changes, breast tenderness, decreased sex drive and acne.
- It might cause bone thinning.
- You have to visit a doctor or clinic every 3 months for the injection.
- The contraceptive injection does not protect you against sexually-transmitted infections (STIs).
Who should not have contraceptive injections?
You should not have the injection if you:
- want to become pregnant soon
- have breast cancer
The contraceptive injection may not be suitable if you:
- have unexplained vaginal bleeding
- have had breast cancer before
- have serious liver disease
- are at risk of, or have a history of, cardiovascular disease (heart disease and stroke)
- are at risk of low bone mineral density
- are aged 50 years or older
Resources and support
Family Planning Australia has fact sheets on contraception.
You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.
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