A New study He suggests a possible alternative to the abortion pill mifepristone, a drug that remains the target of lawsuits and legislation by abortion opponents.
But the potential substitute could further complicate reproductive health policies because it is also the main ingredient in the morning-after pill.
new study, Published Thursday in the journal NEJM Evidenceincludes a drug called ulipristal acetate, which is the active ingredient in the medical contraceptive Ella, one of two types of birth control pills approved in the United States. (The other, Plan B One-Step, which does not require a prescription, contains a different medication and does not work in a way that would end the pregnancy, according to scientific evidence.)
In this study, 133 women who were up to nine weeks pregnant took a double dose of ulipristal acetate found in Ella, followed by misoprostol, the second drug used in a typical medical abortion regimen. All but four of the women completed the termination of their pregnancy without further intervention, a 97 percent completion rate similar to the regimen using mifepristone. (Others completed the process with medications or an additional procedure.)
There were no serious complications, and the study concluded that the use of ulipristal acetate in the two-drug medical abortion regimen was safe.
Dr. Beverly Winikoff, lead author of the study and president of Gynuity Health Projects, a reproductive health research organization, said that after the Supreme Court struck down the national right to abortion in 2022, she began to wonder about the possible role of ulipristal acetate. Which has a chemical structure similar to mifepristone.
“I was thinking, ‘Maybe there’s something else we can do,'” she said. “Another option. This is already on the market.”
The political implications of this study are complicated by its potential to blur the line between public perception of emergency contraception and abortion. For years, abortion opponents have argued against the pill by saying it can cause miscarriage, and reproductive health experts have responded by pointing to scientific evidence that suggests the pill does not end pregnancy but instead works to prevent pregnancy after sex.
Some reproductive health experts worry that research showing a component of the morning-after pill can be used to miscarry could fuel attempts to crack down on emergency contraception and sow confusion that could reinforce the larger anti-abortion strategy.
Christy Hamrick, a spokeswoman for Students for Life of America, said her organization would “absolutely” consider filing a lawsuit over Ella.
“The pro-life movement must be vindicated,” Ms. Hamrick said. “We’ve been saying for years that Ella is an abortionist.”
Mary Ziegler, a law professor and abortion expert at the University of California, Davis, said the study could pose challenges for both sides of the abortion debate.
“It will put a wind in the sails of abortion opponents who have been saying things like contraception can be abortive,” she said, adding: “I think this study that is coming out will be difficult for abortion rights supporters to manage.”
But Ms. Ziegler said the study results could also be “politically risky” for abortion opponents because public support for contraception is high and because many voters in conservative states supported ballot measures protecting abortion rights. “I think that’s one of the things that will tempt social conservatives to push faster than politics currently allows for contraceptive regulation,” she said. “I think that could backfire.”
Reproductive health experts said that the new study did not refute scientific evidence proving that birth control pills do not lead to miscarriage, because they include a different dose of the medication.
Abortion opponents said they were not surprised by the study’s results.
“After years of denying that ulipristal acetate can end the life of a fetus, abortion advocates are now beginning to use it as an alternative to the abortion drug mifepristone,” said Dr. Donna Harrison, director of research at the American Association for Life Support. Obstetricians and gynecologists said in a statement. “The reason for this is simple. Ulipristal and mifepristone work the same way.
Ella has already been a target of some conservatives. Project 2025the right-wing policy blueprint that was Strongly connected The new Trump administration said Ella should be removed from insurance coverage required for contraception under the Affordable Care Act because she is a “potential abortifacient.”
Mifepristone, the first pill in the standard two-drug abortion regimen, is the only drug approved specifically for abortion in the United States. Mifepristone is usually used during the 12th week of pregnancy, and stops the progression of pregnancy by blocking the hormone progesterone. The second medication, misoprostol, is taken 24 to 48 hours later and causes contractions similar to a miscarriage.
Dr. Daniel Grossman, a reproductive health physician and researcher at the University of California, said that ulipristal acetate belongs to the same class of drugs as mifepristone, and it also inhibits the activity of progesterone, which is the hormone that prepares the uterus to receive and carry the fetus. San Francisco, which was not involved in the new study.
In the study, the 60-milligram dose of ulipristal acetate (twice the 30 milligrams in Ella) was replaced by mifepristone and followed by misoprostol, which has different medical uses and has not been targeted to the same extent by abortion opponents. (Misoprostol can also facilitate abortion on its own, but is considered more effective in a combination regimen.)
Reproductive health experts said they welcome the search for alternatives to mifepristone as abortion opponents make efforts to sharply restrict the drug across the country, particularly with Federal lawsuit against the Food and Drug Administration. The Supreme Court dismissed that suit last year, ruling that the first plaintiffs lacked standing to sue, but the suit has since been heard. It was revived with three states as plaintiffs.
Dr. Grossman who wrote Editorial About the study, he said the prospect of finding an alternative to mifepristone is “certainly a promising result.” But he added: “If because of this new evidence that at higher doses, ulipristal acetate can cause miscarriage, leading to ulipristal acetate being withdrawn from the market for emergency contraception, that would be really bad.”
Perrigo, the manufacturer of Ella, issued a statement saying that because the new study tested ulipristal acetate at a higher dose than a single Ella pill, and in combination with misoprostol, “there is still no evidence to show that Ella alone causes miscarriage.” The company added, “Ella is a FDA-approved emergency contraceptive pills that work before pregnancy occurs.
The study was conducted in Mexico City and co-led by researchers there.
Several experts said that because it was a relatively small preliminary study with no comparison group of patients, more research is needed before ulipristal acetate can be used as an alternative to mifepristone in a dual-drug regimen. “We cannot change clinical practice based on this study,” said Kelly Cleland, a researcher and executive director of the American Society for Emergency Contraception.
Scientists have long recognized that hormone-based medications may be able to play different functions at different doses along the spectrum of a woman’s reproductive health cycle.
In Europe, researchers, including Dr. Rebecca Gomperts, a Dutch doctor and founder of telemedicine organizations that provide abortion pills globally, are studying low doses of mifepristone as a weekly pill. Dr. Gomperts said she considered the new ulipristal acetate study sufficient to prescribe the drug off-label with misoprostol.
“The more we use these drugs, the harder it is for people to get off them,” said Dr. Paul Blumenthal, a professor emeritus of obstetrics and gynecology at Stanford University who was on an advisory group for the study.
Plan B is the most widely used morning-after pill in the United States, but Ella is more effective for some women, including overweight people. Plan B is meant to be taken within three days after unprotected sex, while Ella can be taken within five days.
Scientific studies have shown that both pills prevent pregnancy by preventing ovulation, that is, the release of eggs from the ovaries before the eggs are fertilized.
The claim by some abortion opponents that morning-after pills are abortifacients is based on the theory that they may also prevent the implantation of a fertilized egg in the uterus. Most scientific research has not found this to be the case.
For years, though Scientific evidence to the contrary is detailed in a New York Times investigation, The FDA-approved label and packaging for Plan B One-Step said that although the pill works by preventing ovulation, there is a possibility that it may prevent implantation. In 2022 the agency Changed the language To clarify that Plan B only works before fertilization, “it will not work if you are already pregnant, and it will not affect your current pregnancy.”
the FDA label Because Ella says its “potential primary mechanism of action” is to stop or delay ovulation. The label adds that the drug may also affect the implantation process. But studies conducted in recent years Point out that Ella does not work by preventing a fertilized egg from implanting In the womb.
