Effectiveness depends on getting injections regularly: Risk of pregnancy is greatest when a woman misses an injection.

• As commonly used, about 4 pregnancies would be expected per 100 women using progestin-only injectables over the first year. This means that 96 of every 100 women using injectables will not become pregnant.
• When women have injections on time, less than 1 pregnancy would be expected per 100 women using progestin-only injectables over the first year (specifically, just 2 pregnancies would be expected per 1,000 women using this method).

Return of fertility after injections are stopped: Fertility takes an average of about 4 months longer to return for DMPA and 1 month longer for NET-EN compared with most other methods (see Question 8).

Protection against sexually transmitted infections (STIs): None