It depends what method of birth control you are talking about.
- Depot medroxyprogesterone (the shot) can take 6–9 months to go back to normal.
- The pill/patch/ring – in 3 days you go back to normal.
- The IUD – you can go back to normal within 1 week of removal, possibly sooner.
- The implant – same as the pill/patch/ring.