Dr Eva - cycles

Hi Dr Q - is it hormones that effect the length of a period? Mine used to last 5 days and now past couple of years last anything up to 9 - 10 days. The last 5 days are very light (pantie liner more that sufficient). What causes it to last so long? Can this effect fertility? I seem to ovulate around the 14 day mark (cm with blood tinge). I am wondering of this longer period is a hormone imbalance and if so does this effect fertility. (I know there is not a serious problem with uterus etc as had smears and u/s done all ok). My gynie had no explanation of the period length and it was not an issue to me at the time as was not ttc.Thanks!!