Mifepristone Antagonization with Progesterone to Avert Medication Abortion: A Scoping Review

The safety and efficacy of mifepristone antagonization with progesterone to avert medication abortion, also known as abortion pill rescue, is a subject of vigorous debate. Two prominent medical associations have taken positions that either entirely reject or fully support its use. This scoping review aimed to gain insight into the safety and efficacy of its use. Analysis of 16 studies showed that the continuing pregnancy rate after ingesting mifepristone alone is ≦25 percent for gestational ages ≦49 days. Analysis of four studies showed that two-thirds of the women who changed their minds and received progesterone after initiating their medication abortion with mifepristone could safely continue their pregnancies. There is no increased maternal or fetal risk from using bioidentical progesterone in early pregnancy. If a woman has already taken mifepristone for her medication abortion and then changes her mind, timely supplementation with progesterone may allow her pregnancy to continue. The conclusion that mifepristone antagonization with progesterone is a safe and effective treatment has implications for medication abortion informed consent. Summary: Two-thirds of the women who changed their minds and received progesterone after initiating their medication abortion with mifepristone could safely continue their pregnancies. If a woman has already taken mifepristone for her medication abortion and then changes her mind, timely supplementation with progesterone may allow her pregnancy to continue. Physicians should disclose this treatment option to their patients at the time of informed consent.