What's the failure rate of using shots for first time in preventing pregnancy?how many days after getting it should we have sex?

Depo provera (medroxyprogesterone): If Depo Provera (medroxyprogesterone) given correctly you should have some protection this first month. However, what i tell my patients is no unprotected sex the first 30 days. So, use a condom if the shot was recently given. The majority of Depo-Provera related pregnancies i see are women having unprotected sex the first 30 days and women getting the shot off cycle or late.

Low: The pregnancy rate on Depo Provera (medroxyprogesterone) is very low. The failure rate for injections is actually lower than having a tubal ligation in some reports. It is a powerful injection for birth control and is effective immediately. However, most doctors recommend a back up method of birth control for the first month.