How it works

Releases the hormone progestogen which stops ovulation, thickens cervical mucus to prevent sperm reaching an egg, and thins the lining of the uterus (womb) to prevent a fertilised egg implanting.

  • Over 99% effective, lasts for 12 weeks (Depo-Provera) or eight weeks (Noristerat).
  • You can use it if you are breastfeeding.
  • You don’t have to think about contraception for as long as the injection lasts.
  • Not affected by other medicines, diarrhoea or vomiting.
  • Periods may stop, be irregular or last longer.
  • Periods and fertility may take time to return after stopping the injection.
  • Some women gain weight.
  • The injection cannot be removed from the body so any side-effects may continue for as long as it works & for some time afterwards.