How long does the shot stay in you after you get it?

A: A health care provider will inject the shot (brand name Depo-Provera) every 12 weeks to prevent pregnancy. Protection begins immediately if the shot is given within the first five days of your period. If not, use a backup method of birth control — like condoms — for the first week. The shot will reduce the risk of pregnancy for three months. …

Help! It’s been eight months since my last shot of Depo, but I still haven’t gotten my period.

A: It may take up to a year for periods to return after a woman's last shot. Periods become fewer and lighter for most women who get the shot, and often stop altogether. The longer a woman uses the shot, the more likely her periods will stop. …