Does ‘Abortion Reversal’ Actually Work?

Deciding what to do with an unintended pregnancy is likely one of the most challenging decisions anyone can make. Estimates show that 1 in 4 women in this situation will choose to end a pregnancy. Some women may reach the decision to end their pregnancy easily. For others, it’s more difficult. But once they reach a decision, most women do not change their minds. 

However, there are reports of women who have changed their minds and were able to “reverse” their medical abortion. We’ll explain what that means and what experts have to say about it. 

How is an ‘abortion-reversal pill’ supposed to work?

First, it helps to understand how a medical abortion works. It uses two different medications dosed over 2 to 3 days: 

• The first medication is mifepristone. This stops the pregnancy by blocking the hormone progesterone. Progesterone is necessary for a pregnancy to grow. 

• The second medication is misoprostol. This is taken 24 to 48 hours after mifepristone. It causes the uterus to contract and expel the pregnancy.

Advocates for medical abortion reversal suggest that taking progesterone after mifepristone — and before misoprostol — would undo the effects of mifepristone. Since mifepristone works by blocking progesterone, they believe that taking progesterone can stop a medical abortion. 

Can you actually reverse a medical abortion? 

There is very little evidence to suggest this works. Some case series describe situations in which some women were able to stay pregnant by taking progesterone after the initial dose of mifepristone. 

As far as scientific research goes, there isn’t any good quality evidence to support this practice. There are also no studies to compare it to the standard of care because there isn't a standard of care for abortion reversal.

A group of researchers attempted a high-quality study on abortion reversal with progesterone. But they ended the study early due to safety concerns (excessive bleeding). So they were unable to figure out how well it may have worked. 

Simply put, there is not enough scientific data to confirm that this method is either safe or effective. The American College of Obstetricians and Gynecologists considers abortion reversal to be unethical and potentially dangerous. 

What is the success rate of abortion reversal?

No reliable studies confirm a success rate of abortion reversal. Available reports say 67% of women were able to continue their pregnancies when they took progesterone after misoprostol. But it’s difficult to draw any conclusions from case studies and reports. 

It’s also important to note that taking mifepristone alone, without taking progesterone, can result in ongoing pregnancy up to 46% of the time. So it’s hard to say whether progesterone is having the intended effect. The chances that a medical abortion will work depend on the dose of medications and how far along the pregnancy is. Medical abortion is more likely to work earlier in pregnancy. 

What are the known risks of abortion reversal?

The high-quality trial mentioned above ended early due to safety concerns. A few people in the study had significant bleeding that required further care. This suggests that stopping a medical abortion or trying to reverse it may increase the risk of bleeding.

Other side effects of progesterone include nausea, vomiting, and fatigue.

Why trust our experts?

Written by:

Katherine Killoran, MD

Katherine Killoran, MD, is a board-certified gynecologist with more than 20 years of clinical experience.

Edited by:

Mandy Armitage, MD

Mandy Armitage, MD, has combined her interests in clinical medicine with her passion for education and content development for many years. She served as medical director for the health technology companies HealthLoop (now Get Well) and Doximity.

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