It is not an abortion pill, but rather a medication that can help prevent implantation of a fertilized egg.

Insufficient evidence exists on whether changes in the endometrium could actually prevent implantation.

However, excessive E2 will prevent implantation from taking place.

Emergency contraception pills work by preventing ovulation, fertilization, or implantation.

And what if studies show that, in fact, both drugs can prevent implantation?

However, some methods might have a secondary effect of preventing implantation, thus allowing the zygote to die.

These changes in the endometrium could, theoretically, prevent implantation.

"Anything that prevents implantation in our ethics is considered an abortifacient," says Msgr.

More generally the field of immunocontraception includes related technologies that prevent embryonic implantation.