Associate Clinical Professor, St. John's University College of Pharmacy and Health Sciences
314 Answers 7,147 Helpful Votes 25 Followers
Birth control pills are out of your system in a day or two after you stop taking them – which is why you need to take them every single day in order for them to be effective.
The injectable forms of birth control, such as Depo-Provera, are designed to provide contraception for three months. But it can take up to nine or 10 months to be completely dispelled. After three months since your last injection, this form of birth control can no longer be guaranteed as an effective contraceptive.
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