Even for the morning after pill, the main mechanism is to prevent/delay ovulation that cycle. It theoretically can reduce the likelihood of implantation, but it’s less effective at that mode of prevention. And if the embryo already implanted, it will do nothing.
Plan B One-Step works before release of an egg from the ovary. As a result, Plan B One-Step usually stops or delays the release of an egg from the ovary. It is one tablet that contains a higher dose of levonorgestrel than birth control pills and works in a similar way to prevent pregnancy.
Evidence does not support that the drug affects implantation or maintenance of a pregnancy after implantation, therefore it does not terminate a pregnancy.
Even for the morning after pill, the main mechanism is to prevent/delay ovulation that cycle. It theoretically can reduce the likelihood of implantation, but it’s less effective at that mode of prevention. And if the embryo already implanted, it will do nothing.
From the FDA:
Interesting, guess I missed that bit back in sex ed