The injection is a Long Acting Reversible Contraception.

The most common one used is Depo-Provera which works by releasing progestogen into the bloodstream, preventing the release of an egg during ovulation. It also thickens mucus in the cervix, making it harder for sperm to get to the egg, and thins the womb, reducing the chance of the egg implanting.

The injection is usually given in your bottom but can also be injected into the upper arm. Once this has been done, you will only need to go back when your next one is due, unless you have any problems.

You can have the injection at any time and will be protected straight away if it is given in the first 5 days of your cycle. However, if it is outside of this window then you will need to use additional protection, like condoms, for 7 days.

The contraceptive injection is available for free at GP surgeries, GUM clinics and contraception clinics. If you aren’t sure where your nearest clinic is, you can enter your postcode here.


  • Over 99% effective.
  • Lasts for 8 or 13 weeks depending on which one is given.
  • Good choice for women who struggle to remember to take the pill.
  • Other medicines don’t affect the implant’s effectiveness.
  • Suitable for those who can’t take oestrogen.


  • It can take up to a year for your fertility to return once the injection has run out.
  • Periods can become irregular or stop completely.
  • The contraceptive injection does not protect you against sexually transmitted infections, so you will need to use condoms as well.
Click for more contraception options