You have 72 hours to prevent an unplanned pregnancy after unprotected sex. Pregnancy is established only after the fertilized egg attaches itself to the womb. This process can take 2 to 4 days. You need to act within this time frame to avoid the risk of pregnancy.

You should take i-pill as soon as possible and not later than 72 hours. The sooner you take i-pill, the more effective it is. i-pill is 95% effective within 24 hours of unprotected sex, 85% between 25-48 hours and 58% if taken between 49-72 hours.