What is it? It's an injection of hormones that provides a longer-acting alternative to the pill. It works by slowly releasing the hormone progestogen into the body to stop ovulation. Each injection lasts for 8-12 weeks depending on what type is chosen (Depo Provera lasts for 12 weeks and Noristerat lasts for 8 weeks).
Advantages: Unlike the pill you don’t need to remember to take a tablet every day. It doesn't interrupt sex and can be used by women who cannot take oestrogen. It may reduce heavy or painful periods and it may give some protection against cancer of the uterus.
Considerations: Periods can become irregular or stop altogether. It can take over a year for fertility to return to normal after stopping contraceptive injections, so if you are planning to start a family in the near future, it may not be suitable. It's important to remember to attend your appointments on time every 8-12 weeks, otherwise contraceptive cover can stop. Injections do not offer protection against sexually transmitted infections or HIV/AIDS. The doctor will run through all side effects with you fully at the time of your appointment but these could include spotty skin, headaches, tender breasts, changes in mood and sex drive and weight gain.
Available from? GP, family planning clinics, Marie Stopes International centres.
How effective? 99%, less than four women in every 1,000 will get pregnant over two years.