How long does birth control stay in your system if you stop taking them after 4 years?

Birth control: Even if you have been on birth control pills for four years, they will certainly be gone from your system after a month.

Soon enough: BC pills work by tricking your body into believing you are pregnant, so you preserve eggs for later.(don't ovulate).When you stop the pill the hormone level begins to fall, and at some point (unknown) you resume releasing eggs, so if /when you decide to stop, use another form of BC unless you want to get pregnant.