What Causes Delayed Periods After Taking Regestrone?

my periods is on 11th. I want to prepone my periods. so i took registrome for two days i.e., 4th two tablets (aft & ngt) 5th three times a day. still i didn t get my periods. today is 7th. Before 9th i want to get periods. it will postpone ? I dont want to postpone. my periods are regular every month. please answer. 0