Rx aygestin for painful periods. i do not bleed heavy and only for 3 days. will this cause me to bleed more or have breakthrough? i have regular scheduled periods now. why do you start it on day one of period? effect of starting at the end of period?

Same: Aygestin is progesterone and used for both painful or heavy bleeding periods. The progesterone helps decrease menstrual cramping and therefore the pain. The progesterone level normally drops when you have your period and so by taking it starting the first day of your period, the drop is not as much. However, if you take progesterone later, you may bleed or spot when you stop taking it.