Since a woman can never know when she has ovulated, working out the exact point of fertilisation is also impossible. What we do know is that implantation occurs 6-12 days after fertilisation.1 Once implantation is complete, pregnancy is established.2
Pregnancy begins when a fertilised egg has been implanted in the wall of a woman’s uterus. This definition is critical to distinguishing between a contraceptive that prevents pregnancy and an abortifacient that terminates it.2,3
Many women don’t understand when pregnancy begins. They believe it starts the moment they had UPSI. Within 5 days of UPSI a woman cannot be pregnant from that UPSI, because implantation cannot yet have occurred. But this mistaken understanding means that they can feel guilty about using EC because they wrongly believe it to be a form of abortion.4
