Hello, My girlfriend has been on birth control for about 3 months now. We have protected sex every time, and just this past wednesday, december 5th, she had her period a day early. But missed her birth control that same day as well. She had regular flow BUT only for 1 day. She said there was no spotting or anything, just a regular day flow. But nothing the day after. Could this be due to the birth control, because she missed that day, or should we be concerned she is pregnant? If I remember correctly, if you bleed during your expected period that the uterus has shed its walls and there is no way for the egg to implant, right?