The morning after pill (not to be confused with the abortion pill) is also sometimes called emergency contraception or “Plan B.” The morning after pill can be used as emergency contraception if no contraception was used or the contraception method (condom, pill, injection, etc.) failed.
The morning after pill (MAP) is most effective taken immediately after unprotected sex. It can be taken up to 3 days or 72 hours after unprotected sex, but might be less effective.
The MAP stops sperm from fertilizing an egg: it prevents pregnancy, but it cannot end a pregnancy after fertilization.