Q: Can you get pregnant even if you took a Plan B pill a day after sex?
A: The short answer is yes, but your chances of getting pregnant are greatly reduced. Plan B is about 95% effective in preventing pregnancy when taken within 1 day of having unprotected vaginal intercourse. Its effectiveness decreases each day after that.
The reason why it’s not 100% effective is that Emergency Contraception (like Plan B) works by stopping ovulation (the releasing of an egg cell from the ovary). If there’s no egg cell in the system, there’s no way to get pregnant. But, if a woman has ovulated before she takes Plan B that egg will not be stopped and can be fertilized by a sperm cell.