Why a flawed study on medication abortion was retracted

Earlier this month, the academic publisher Sage retracted three studies that had run in one of its scientific journals, citing a “lack of scientific rigor.” One of these studies had received particular attention in the context of a court case attempting to restrict access to the medication abortion drug mifepristone — a case with potentially far-reaching implications that will soon be heard by the Supreme Court.

Taking a closer look at this study shows that the decision to retract it was justified — and exposes the larger context in which unsound science is used to drive an anti-abortion agenda in courts and legislatures.

Mifepristone is not a new drug. It was first approved by the FDA in 2000 and had been used globally long before then. The extensive approval process at the time — and over two decades of actual use in the U.S. since then — have provided overwhelming evidence that mifepristone is safe and effective, and that serious complications are very rare.

The retracted 2021 study claims that mifepristone has a much higher rate of complications than previous research had found — making the study a clear outlier in the larger body of evidence. A study that goes against the established scientific consensus does not necessarily mean it’s wrong, but it does mean its findings and methodology deserve close scrutiny. And that’s where the retracted study falls far short.

After concerns about the study were raised, the journal asked outside experts to conduct a post-publication peer review. This review found “fundamental problems with the study design and methodology, unjustified or incorrect factual assumptions, material errors in the authors’ analysis of the data, and misleading presentations of the data that … demonstrate a lack of scientific rigor and invalidate the authors’ conclusions in whole or in part.”

Nobody from the Guttmacher Institute, the organization we are affiliated with, was involved in this post-publication peer review, but one of us (Jones, a principal research scientist at Guttmacher) independently reviewed this study. Using Medicaid claims data from 17 states where coverage for abortion was available between 1999 and 2015, the study authors examined emergency room visits among people who had had a medication or a procedural abortion. There were two major issues with this paper that justify the retraction.

First, the study used an inappropriate measure. The researchers considered any and all ER visits that occurred within 30 days of a medication or procedural abortion to be the direct result of the abortion. That’s a serious flaw, as people visit ERs for many reasons — they are a first source of care for many people living with low incomes who lack a primary care provider, particularly those insured through Medicaid. Focusing on all-cause ER visits is inappropriate and assumes that patients who had an abortion had no other reason to visit an ER.

Second, the researchers put this inappropriate data point front and center in their article, even though their own paper included more relevant and accurate data. In the article, the authors provided information specifically on abortion-related ER visits, showing a rate of abortion-related visits (1-5 percent) similar to those in prior research using Medicaid claims data and published in a top medical journal. In other words, the authors intentionally focused on the inappropriate measure of all ER visits to falsely assert that up to 34 percent of medication abortions in 2015 resulted in ER visits.

The post-publication review raised other flags. One of the study’s original peer reviewers was associated with the same self-described anti-abortion organization as the authors (the Charlotte Lozier Institute), which raises questions about the objectivity of their review. When a journal asks a Guttmacher researcher to review a scientific manuscript submitted by another researcher at the Institute, we decline, as it would be a clear conflict of interest for us to evaluate the research of close colleagues in this context.

More generally, the study also fails the basic plausibility test. Mifepristone is used in well over half of all U.S. abortions and has been used over 5 million times in the U.S. since it was approved. If it was as dangerous as anti-abortion groups are claiming, emergency departments would be filled with patients suffering from complications. That is simply not the case.

Published scientific papers are retracted all the time, including ones by Nobel Prize–winning scientists. The retraction of the studies affiliated with the Lozier Institute is not some dark conspiracy, it’s the scientific process working as intended; it was based on a closer evaluation of the authors’ erroneous methods and misleading presentation of data to support inaccurate conclusions.

But this is not just an academic debate — there are serious real-world implications. Currently, 14 states ban abortion entirely — and the anti-abortion movement’s declared goal is to ban it everywhere, including in states where it is currently protected. Restricting mifepristone is part of this larger strategy.

Anti-abortion activists first filed their baseless case in 2022, cynically “judge shopping” to have a judge with strong anti-abortion views assigned to their case. As expected, Judge Matthew Kacsmaryk issued a decision rolling back mifepristone access that ignored most of the evidence and instead cherrypicked just a few outlier studies — the retracted study prominent among them. The conservative Fifth Circuit Court of Appeals then upheld most of that decision. The case will now be heard on March 26 by the same Supreme Court that overturned Roe v. Wade less than two years ago.

Faulty science is being weaponized to attack not just Americans’ right to health care and bodily autonomy, but also to undermine the integrity of the scientific process and our entire judicial system.

We deserve better. And that’s why the Supreme Court has only one reasonable option in this case — honor the FDA’s evidence-based decisions around mifepristone and preserve access to medication abortion without any medically unnecessary restrictions.

Rachel K. Jones is a principal research scientist and Kelly Baden is vice president for public policy with the Guttmacher Institute, a research and policy organization working to advance sexual and reproductive health and rights globally.