If you start taking hormonally active pills when your period starts, the bleeding will stop soon thereafter. If you continue taking hormonally active pills all the time, you will skip a few periods but that can’t go on forever. At some time, you will start bleeding larger amounts of blood. The purpose of hormonal contraception (birth control pills) is to prevent unwanted pregnancy in a way that will not to disturb the normal cycles and periods. That’s why the birth control pills are also used as a therapy for irregular cycles. Having a regular and normal period is very important for a woman. If there is a constant hormonal stimulation (without hormonal withdrawal) the endometrium will proliferate all the time (hyperplasia). The vascular capacity of the uterus and the space contained by the uterus are limited so that the endometrium will start to degenerate and die. This is manifested with profuse vaginal bleeding. Besides heavy bleedings, constant hormonal stimulation over a longer duration can cause transformation of the hyperplasia into cancer.