Postinor 2 can prevent pregnancy?i had sex after 10days from my last period.then i take postinor 2 after 5days from had sex.

5 days...may be late: Plan B, Postinor 2, and other brands of emergency contraceptive pills can alter the menstrual cycle for the cycle in which Plan B or Postinor 2 was taken, and sometimes the next month's cycle too. One should be sure to check a home pregnancy test about 3 weeks after sex, because emergency contraceptive pills work most of the time, but not all the time.