Just when you thought your time of the month is over you start spotting unexpectedly before your next period. While you may ignore it sometimes it could be downright alarming. Well-known gynecologist Sangeeta Agarwal tells you why you could be spotting in between your periods. You switched started or stopped taking birth control pills Spotting is common in women who have started or stopped taking birth control pills. Estrogen helps keep the uterus lining intact and when you have just started or stopped taking the pill there could be an imbalance in your estrogen levels which could lead to spotting.