I started taking Microgestin Fe 1/20 on June 29th (Monday) at the very end of my period (it started the Wednesday before), which was when my doctor told me to start taking them. The manufacturer label and my doctor told me that it is effective after 7 days of perfect use. Is it less effective the first month you take birth control than the other months? Also, would it be okay to have unprotected sex during week 4 (placebo) of the pack on the first month?