Medication abortion is back at the US Supreme Court—which is exactly where abortion opponents want it. Last week, in a late Friday afternoon move guaranteed to stoke maximum confusion and panic, the Fifth Circuit Court of Appeals blocked a Food and Drug Administration rule allowing telemedicine prescription of mifepristone, one of two drugs that make up the gold-standard abortion-pill regimen. On Monday morning, Supreme Court Justice Samuel Alito put that ruling on pause until May 11.

But even as abortion advocates expressed relief that telemedicine abortions can continue for a few more days, the order by Alito—the same ultraconservative who wrote the Dobbs decision overturning Roe v. Wade in 2022—was at best a reprieve. At some point soon, the court’s right-wing supermajority could drastically curtail or cut off access by mail to an extremely safe and effective drug that has been used by hundreds of thousands of women a year since Dobbs, including in states where abortion is banned. Almost two-thirds of abortions in the US now happen with pills, and nearly 30 percent occur by telemedicine.

Abortion activists have been watching the attacks on mifepristone for a long time, and are prepared with a backup: misoprostol, the second drug in the gold-standard regimen. Developed in the 1970s to protect the stomach lining against ulcers, misoprostol also causes muscles in some parts of the body to contract. “In the uterus,” says Caitlin Gerdts, vice president for research at Ibis Reproductive Health, a nonprofit hub for abortion research around the globe, “what that means is cramping and then expulsion of what’s inside.” While misoprostol works exceedingly well in combination with mifepristone, it is also a highly effective abortion drug on its own. And abortion isn’t the half of it: “Misoprostol has a remarkable range of uses in the reproductive context,” Gerdts says, including induction of labor, miscarriage management, and treatment of postpartum hemorrhage.

Misosprostol is much easier to obtain than mifepristone—in many countries, it’s available over the counter—making it the go-to method of terminating pregnancies in parts of the world where abortion is highly restricted and resources are scarce. If mifepristone is curtailed in the US, misoprostol-only abortions will likely become much more common here as well. Foreseeing that possibility, abortion opponents in Louisiana passed a law in 2024 reclassifying both drugs as dangerous controlled substances. Other states have considered something similar.

Meanwhile, abortion advocates are scrambling to switch to a misoprostol-only regimen if necessary, educating patients about what to expect (the side effects may be harsher), and strengthening legal networks, medical hotlines, and community support systems so that women don’t put themselves at unnecessary risk. Winning over medical providers unfamiliar with the drug is critical. “Despite the fact that very good evidence exists for misoprostol’s effectiveness,” Gerdts says, “it’s really hard for clinicians to know what to believe or how to interpret it.”

Amid an increasingly hostile research environment, Ibis has launched US clinical trials comparing the two-drug regimen with misoprostol alone—the first such head-to-head study in the world. To learn more about the study and what may lie ahead for the misoprostol-only regime, I reached out to Gerdts, an epidemiologist by training, at her office in Oakland, California. Our conversation has been edited for length and clarity.

How did misoprostol become widely used as an abortion pill? It started in Latin America in the 1980s.

The origin story of misoprostol as an abortifacient is one of community need and innovation and discovery. It starts with pregnant people in Brazil reading the warning label for Cytotec, the brand name of misoprostol, which was available as an ulcer drug in a lot of pharmacies in Latin America. The label suggested that this was a medication that might cause a miscarriage. At the time, and still to this day, abortion was highly restricted in Brazil and across much of the region. So people started using misoprostol to terminate their pregnancies. They would end up having something that looked very much like a miscarriage, with bleeding but far fewer infections.

Soon, feminist activists........

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