The overturning of Roe v. Wade has put a spotlight on a small manufacturer of abortion pills, which are emerging as a flashpoint between advocates and opponents of the procedure.

Abortion-rights advocates have for decades lobbied for more access to mifepristone, the abortion medication that Danco Laboratories LLC manufactures under the brand name Mifeprex and sells for about $50 a pill. They want the Food and Drug Administration to remove safety restrictions on the drug, make it available without a prescription or expand its label to approve it for miscarriage, for which it is also sometimes prescribed, off label. An official use for miscarriage would help ensure women experiencing a miscarriage could get the drug. It might also make it more difficult for prosecutors to investigate doctors who dispense the pills in states where abortions are banned, abortion-rights advocates said.

Antiabortion activists participated in a protest last month in Washington.

Photo: Alex Wong/Getty Images

The FDA has said Danco would have to present data demonstrating that the medication is safe under those circumstances. Privately held Danco said it doesn’t currently plan to ask the FDA for an expanded label or approval for use after miscarriage.

“There are always voices within this community that want to see us go further and do more than what we’ve done,” said a Danco spokeswoman. “We try to be very pragmatic about our approach to things and do as much as we can within the box that we’re in.”

The pills used to conduct what are known as medication abortions are becoming hotly contested in the U.S. Even before the Supreme Court overturned Roe v. Wade last month and states began adding restrictions on abortion, the pills accounted for more than half of abortions in the U.S. according to the Guttmacher Institute, a group that supports abortion rights and tracks abortion-related statistics.

Enforcing abortion bans where pills are available could be difficult because they can be sent through the mail and taken at home.

Photo: Charlie Neibergall/Associated Press

Enforcing abortion bans where pills are available could be difficult, policy experts said, because they can be sent through the mail and taken at home. The Biden administration has said it would defend people’s right to take the drug.

Abortion opponents have pressed states to restrict the use of abortion pills. Nineteen states have laws that require doctors to prescribe them in person, according to Guttmacher. Some require patients to return for a follow-up visit or have other restrictions.

State bans on abortion taking effect following the overturning of Roe v. Wade also apply to the pills. Abortion opponents have sought to highlight risks of the drug and said they plan to submit to the FDA peer-reviewed research showing that women who take the pills are more likely to visit emergency rooms afterward than those who get surgical abortions.

Literature about medication abortions has been available at clinics such as this one in New Mexico.

Photo: robyn beck/Agence France-Presse/Getty Images

Mifepristone blocks progesterone, a hormone necessary for continuing a pregnancy, causing the gestational sac to detach from the walls of the uterus. A day or two after taking it, patients take misoprostol, a drug that causes contractions, pushing out the embryo or fetus and tissue associated with the pregnancy. Patients experience cramps and bleeding. Side effects can include nausea, vomiting and dizziness. In rarer cases women can hemorrhage or become infected.

A generic form of mifepristone made by GenBioPro Inc. has captured a significant share of the U.S. market since it was introduced in 2019, the company said in a court filing. Privately held GenBioPro filed a lawsuit against Mississippi in 2020, arguing that the state inappropriately restricts abortion pills since the FDA has said the drugs are safe and effective. Danco wasn’t a party to the lawsuit.

GenBioPro began distributing mifepristone via telehealth providers and pharmacies during the pandemic, soon after a judge in 2020 ruled the FDA couldn’t enforce an earlier safety restriction requiring women seeking abortion pills to get them from a doctor or other provider in person. Danco followed several months later. The FDA made the change permanent late last year.

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New York City-based Danco, with fewer than 25 employees who now mostly work remotely, said it doesn’t have the resources to do the clinical trials and legal work to ask the FDA for major changes to the allowed use of its product. “The company is very moderately profitable, and the investors only have so much,” the spokeswoman said. “It’s not a bottomless bucket for them.”

Foundations formed by David Packard, George Soros and Warren Buffett helped establish Danco and pay for its clinical trials in the 1990s but aren’t owners of the company, the spokeswoman said. Mr. Buffett supports a small family foundation that backs abortion rights, and officials there plan to receive a massive influx of money from Mr. Buffett’s estate.

Danco’s only product is Mifeprex, and the company maintains a low profile. Its office has no sign, and employees answer its main phone line with a “hello” instead of identifying the company. Danco said its pills are manufactured in Europe. It doesn’t disclose investors, board members or its chief executive for fear they might be targeted by antiabortion activists, the spokeswoman said.

The company’s cautious approach has frustrated abortion-rights advocates. Abortion providers pushed the company for years to request updates to its label. When the company made the move, it relied on outside studies from abortion-rights supporters to show the changes were safe. The FDA in 2016 approved Mifeprex for use to end a pregnancy up to 10 weeks, three weeks longer than its previously approved use.

“They didn’t want to rock the boat I think by making changes,” said Beverly Winikoff, president of Gynuity Health Projects, which advocates for access to abortion pills.

Kirsten Moore, director of the Expanding Medication Abortion Access Project, said she has encouraged Danco to seek FDA approval for Mifeprex to be prescribed for miscarriage. Widening the approved use would dilute its association with abortion, Ms. Moore said.

“Having this drug labeled for the use of miscarriage could expand the pool of providers who are willing to prescribe it for their patients,” she said. “It also complicates the opposition’s narrative of abortion.”

Danco said it is interested in a miscarriage label because there is data to support that use.

“We care very much about access to reproductive healthcare and women’s health,” the Danco spokeswoman said. ”But at the same time it’s a business, it’s a for-profit business that needs to be able to keep its business.”

Write to Liz Essley Whyte at liz.whyte@wsj.com