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

• As commonly used, about 4 pregnancies 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 per 100 women using progestin-only injectables over the first year (2 per 1,000 women).

Return of fertility after injections are stopped: An average of about 4 months longer for DMPA and 1 month longer for NET-EN than with most other methods (see Question 8)

Protection against sexually transmitted infections (STIs): None