If im taking birth control pills to regulate my period, how long before I start bleeding? I haven't had my period in 3 years. I am supposed to start taking them sunday but I need to know about when ill begin bleeding

The. The bleeding should start around the time you start the placebo (sugar) pills at the end of the pack. For most pill packs this is day 21 of the cycle. If you continue not to have your period while on the birth control pills, let your doctor know.