How do I know if the morning after pill has worked?

Getting their next period is how women usually confirm the morning after pill has worked. However, after using a morning after pill it is quite common for the next period to be up to 7 days later than usual, because the morning after pill delays ovulation. 

 

You can confirm whether the morning after pill has worked by doing a pregnancy test on the first day when your next period is due, or if you do not know when it is due you can do a pregnancy test 21 days after taking the morning after pill. If it is negative, you are unlikely to be pregnant.