Is It Safe To Take Asmita And Femilon To Avoid Period And Pregnancy?

How do i use Asmita or Femilon and from when should i use the tablets ? Like my period date are 30th of every month and last month it got delayed by 3 days and i got my periods on 3rd, and now I am getting married on 24th and I want to avoid the periods till 15th of next month, and i was told to take some a tablet each day to avoid periods till 15th. Please let me know is it safe to take both the tablets to avoid periods and to avoid pregancy at the same time ? And if I take Asmita or Femilon from the day I have physical relationship is it safe that I won't get pregnant ? Please suggest ..