Injection Method*

How does it work?

  • Injection that contains only the female hormone progestin (there is no estrogen in this method)
  • Must get the injection every 12 weeks
  • Stops the ovary from releasing an egg (ovulation)
  • Thickens the cervical mucus and makes it more difficult for the sperm to travel into the uterus


  • 97-99.7% effective
  • Each injection last 12 weeks
  • Effective right away if you get your first injection during the first five days of a normal period
  • Only you know you are using this method
  • Allows for unplanned sex
  • Periods may be shorter in length and lighter in flow or you may no longer have a regular period
  • Can be used by women who are unable to use estrogen (for example, women who are 35 and older who smoke)
  • Reversible


  • No protection against STIs, including HIV
  • Side effects may include changes in menstrual bleeding patterns, weight changes, breast tenderness, mood changes, headaches
  • Slower return of fertility - not recommended if you plan to become pregnant in the next 1-2 years
  • Side effects can last up to 6-8 months after the last injection
  • Affects bone density and is not recommended for long term use