The most prominent study supporting the idea that the abortion pill can be “reversed” has been temporarily withdrawn by the pro-life journal that published it. The case series was originally published in April, and it documented the results for 547 women who underwent a controversial hormone therapy after taking the first of two drugs that make up the abortion “pill.” The paper concluded that reversal is “safe and effective.”

Two of the study’s authors are affiliated with the University of San Diego, a Catholic university that began investigating the study shortly after it was published, according to Pamela Payton, a spokeswoman for USD. The journal, Issues in Law & Medicine, has now temporarily withdrawn the study “pending technical corrections.” Issues in Law & Medicine has connections to anti-abortion organizations including the American Association of Pro-Life Obstetricians and Gynecologists. This means that both a Catholic university and a pro-life journal have serious, if technical, concerns about the paper.

Abortion-pill “reversal” was the brainchild of George Delgado, a San Diego OB-GYN who heads a family-medicine clinic with a separate “crisis pregnancy center.” The “abortion-pill reversal” he promotes is an intervention after a woman has taken the first of two medications that constitute a medication abortion: mifepristone and misoprostol. Those medications are usually taken a day or two apart, and a small number of women experience regret after taking the first course of medication. Delgado’s approach is to deliver a large dose of progesterone, the “pregnancy hormone,” as soon as possible—an attempt to overwhelm the mifepristone and preserve the pregnancy. He has developed a hotline and a network of hundreds of doctors, mostly in the United States, who stand ready to administer the procedure. He calls the approach “a second chance at choice.”

Abortion-pill “reversal” was the brainchild of a doctor who called it “a second chance at choice.”

Some pro-choice doctors say there is a plausible medical logic to flooding the system with progesterone. But the idea remained almost completely anecdotal and speculative until Delgado’s study came out in April. That study, published with six co-authors, documented the procedure’s results in 754 women who called the reversal hotline over the course of several years. Among the 547 women who underwent the procedure in the ideal 72-hour window of time, almost half had successful pregnancies that ended in a live birth. Other studies have suggested that roughly 25 percent of pregnancies will continue if the woman simply declines to take the misoprostol, and that lower rate would seem to indicate that the reversal does indeed work in a significant share of cases. Critics point out that some of the women who attempted reversal may have received ultrasounds to confirm their pregnancies were still viable, which could skew the results since some pregnancies that would not have been helped by reversal would be excluded. Regardless, the paper was received triumphantly in pro-life circles: “Study Strikes Startling Blow to Abortion Enthusiasts’ Narrative Against Abortion Pill Reversal,” one column crowed.

Casual readers of the paper would have every reason to think Delgado and his co-authors received permission from an institutional review board—a university-affiliated body that protects the welfare of human research subjects—in conducting their research. The paper states, “This is an observational case series with data analysis that received an institutional review board waiver,” with a footnote that refers to USD. But that sentence structure was misleading. Payton said that USD’s board was asked by a co-author, Jonathan Mack, to approve the analysis of existing data, not the collection of new data—that is, only the “data analysis” in the sentence, not the “observational case series with data analysis,” received approval. Payton said the heads of USD’s institutional review board began receiving written concerns from leading researchers in the field of nursing almost as soon as the paper was published. After investigating, the university asked the authors to withdraw and correct the paper.

In an email, Delgado told me that the problem was a “technical error simply because of an oversight in that the data sample included covered a longer period of time than that which was initially reported to the IRB,” an issue Payton did not mention to me. Delgado expects the new IRB approval to come through within two weeks, which Payton said was possible. Delgado said that “the IRB had no problem with the informed consent nor with approval of the research itself,” and confirmed he was referring to USD’s review board. But Payton emphasized that USD’s approval pertained only to data analysis, and not the study as a whole. USD may have had “no problem” with the original research, but they also were not asked to look at it.

The paper’s withdrawal from the journal may be temporary, but larger questions about Delgado’s work are looming. If USD’s review board did not approve of his research, then who did? Were Delgado and his co-authors conducting clinical research on an experimental treatment without oversight? “If an IRB did not approve their clinical research protocol in advance, we need to question whether this research was conducted ethically or not,” said Daniel Grossman, a professor in the department of obstetrics, gynecology, and reproductive sciences at the University of California–San Francisco and a vocal critic of “reversal,” in part because he argues that it has not yet been responsibly tested. Grossman said he has seen the form that patients who receive Delgado’s treatment are asked to sign, and he does not believe it is sufficient. He emphasized that such matters are exactly what an IRB assesses.

Despite the shakiness of the research on reversal, pro-life activists and legislators have eagerly promoted it—not just as a fringe treatment available to women who seek it out on their own, but as a procedure that all women taking the abortion pill should know about. Since 2015, conservative lawmakers in at least 10 states have introduced legislation that would require doctors to inform abortion-medication patients that “reversal” is available. When such legislation began gathering momentum in the pro-life community a few years ago, the only published research was a case series involving seven women, co-written by George Delgado.