For some reason, a week or two before my last period, I started freaking out that I might be pregnant. My period usually arrives on
Day 4 of the placebo pills, but arrived a
day early, stopped, and then started a few hours later. It remained for the normal amount of time. I was on medication, however, and I keep seeing differing statements about its effect on birth control. The Mayo Clinic says that medication doesn't effect it, but some other sites swear it does.