I have been on the pill for a few months. My period was very regular beforehand and lasted for a normal period of time, about 5 days. Ever since starting the contraceptive, my period falls late within the 7 day pill-free window and when it does come, the flow is not normal either in duration, amount, or color.
I will ask a doctor about this but I am interested in whether this is a common experience and what women have done.