Is Mifepristone, a Drug Used in Medication Abortions, Dangerous?

supreme court ruling on mifepristone
Emma Yasinski
Emma Yasinski Staff Writer
Medically Reviewed By:Gina Jansheski

Experts and medical associations, such as the American College of Obstetricians and Gynecologists, say mifepristone, a drug used alongside misoprostol, in a two-pill regimen used to induce abortion, is safe and effective.1 So, why is the Supreme Court about to make a ruling about whether or not it can continue to be prescribed?

Mifepristone blocks progesterone, a hormone required to maintain a pregnancy, and misoprostol induces contractions to empty the uterus.

In the lawsuit currently in front of the Supreme Court, plaintiffs make several statements about the process by which the U.S. Food and Drug Administration (FDA) approved mifepristone in 2000, and again in 2016 and 2021 when it reduced the required safeguards on prescribing. For example, it was allowed to be prescribed by health care providers other than doctors (such as nurse practitioners and physician assistants) or via telehealth.

The case lays out some claims outside MedShadow’s scope, such as the idea that mailing the pills constitutes a violation of a law banning the mailing of obscene materials. Here, however, we will focus on the group’s claims regarding the safety of these abortion pills, as opposed to any ethical or political arguments.

To read more about the common side effects of medical abortions, read MedShadow’s What to Know About the Abortion Pill Side Effects.

“Decades of data have consistently demonstrated that mifepristone is safe and effective for both medication abortion and management of early pregnancy loss,” said Verda J. Hicks, MD, president of ACOG, in a statement.2 “In fact, over time, additional clinical study of mifepristone has led to an improved regimen with an even better safety and efficacy profile.”

“Conversely, the supposed harms of mifepristone have not been substantiated or have been intentionally misrepresented by opponents of abortion in an effort to limit access to a safe and effective drug,” Hicks continued. “Two of the studies that formed the basis of the respondents’ arguments have been retracted, and the overwhelming majority of complications associated with mifepristone are minor and easily treatable or require no additional intervention at all.”

Below are some of the main safety claims discussed in the lawsuit and the evidence that supports or refutes them.

1. Mifepristone Causes Substantial Harm to Women and Girls.

To demonstrate that abortion pills cause substantial harm, the lawsuit cited a 2011 study in which researchers reviewed the medical records of about 27,000 women in Finland who had induced abortions between 2000 and 2006.3 Participants were limited to pregnancies at no more than 20 weeks of gestation. The purpose of the study was to compare the risks of adverse events between adults and adolescents who used medication abortions.

The lawsuit cites the following statistics from the adult women in the study:

  • 10% needed follow-up care for incomplete abortions
  • 15% experienced hemorrhaging
  • 2% experienced an infection

These statistics are accurate based on the study data, but the authors pointed out that the medical records they reviewed didn’t classify the severity of each event. So it’s unclear, for example, how many of the bleeding events were serious. Carrie Griffin, DO, an osteopathic family medicine physician in Eureka, California, says that heavy bleeding and cramping are typical side effects of medication abortions.

However, it is uncommon for the bleeding to be so heavy that women require emergency care, such as stitches or a blood transfusion.4

2. 5% of Women Will Go to the Emergency Room Within 30 Days of a Medication Abortion.


The lawsuit states that because the pills can cause more complications than surgical abortions, the FDA’s approval was flawed; the pills did not provide a meaningful benefit over the existing treatment, surgical abortions. To prove this point, the suit cited a study that reported 5% of women will go to the emergency room within 30 days of having a medication abortion.5

However, that study has been retracted.6 The journal that published it worked with statistical experts and determined that the presentation of the data was misleading, its conclusions inaccurate, and that the authors failed to disclose their connection to a pro-life organization, constituting a conflict of interest.

A separate study published in 2018 found that 51% of emergency room visits after abortions required no care other than observation.7 In many cases, a woman may have come to the hospital unsure if her bleeding was excessive, for example. She may have been observed by the staff for a brief period before they determined she was healthy and could go home. One caveat is that this study included both surgical and medication abortions.

3. After a Second-Trimester Medication Abortion, 39% of Women Need Surgical Evacuation.

Surgical evacuation is the procedure in which a doctor empties the uterus. The case cites a 2011 study of the Finnish abortion registry that compared the complications from abortions done in the first trimester (0 to12 weeks gestation) and second trimester (13 to 26 weeks gestation).8 The study did, indeed, find that 39% of women who had medication abortions during the second trimester went on to have surgical evacuation.

However, the authors pointed out a very important caveat. Up until the year 2000, it was standard procedure to perform a surgical evacuation after a medical abortion. The study reviewed abortions that took place between the years 2003 and 2006. They pointed out that the rate of surgical evacuation during 2001, 45 to 64%, was higher than it was during the study period. This suggests that the high rates are not due to incomplete abortions but because doctors were gradually transitioning to the new protocol.

Despite the frequency of surgical evacuation, the rate of serious adverse events that required surgical repair was only 0.3% for second-trimester medication abortions and 0.1% for those completed during the first trimester.

4. After Six Weeks Gestation, Risks Escalate.

This claim is important because in 2016, the FDA extended the indication for mifepristone use from abortions of fetuses under 49 days gestation out to 70 days gestation. Lengthening this period by just three weeks increased the proportion of abortions in the U.S. that are eligible for mifepristone, which had been 37%, up to 75%.9

Few studies compare early versus late first-trimester medication abortions, but one 2019 review of nine studies concluded that the limited evidence that does exist suggested that adverse events remained rare at 10 weeks despite a slightly elevated risk of heavy bleeding.10

5. Chemical Abortions Can Cause Problems in Future Pregnancies if Given to a Woman with Rh Negative Blood Without Treatment with Rhogam

About 14.6% of people in the U.S. have blood that lacks a protein called Rhesus (Rh) factor.11 For these individuals, the word “negative” is included in the name of their blood type. For example, someone with O negative blood does not have Rh factor. Someone with O positive blood does have Rh factor.

Normally, being Rh-negative is not a problem, but if you are carrying a fetus with Rh-positive blood, your body could produce antibodies against its red blood cells that could lead to anemia.12 These antibodies can also harm a future fetus if you become pregnant with another Rh-positive fetus.

Typically, you will receive a blood test early in your pregnancy to determine if there’s a mismatch. Then, you’ll be given treatment to prevent your body from producing antibodies that could attack your fetus’ blood. In order for you to form these antibodies, your blood has to mix with that of your fetus, and this rarely happens early in pregnancy. Most often, doctors provide this treatment at about 28 weeks of pregnancy and right after the baby is born (if found to be Rh positive).

A 2023 study published in the Journal of the American Medical Association suggested that testing for Rh factor prior to a first-trimester abortion is unnecessary.13 That is because the study found only 1 out of 506 Rh-negative participants had been exposed to enough fetal blood cells to trigger the production of antibodies during the first trimester that could cause future problems.

6. The Risks of the Drug for Adolescents Are Unknown Because the Agency Did Not Adequately Study Use in Adolescents.

The suit alleges that the studies the FDA relied on to assess the adverse effects of medication abortion on adolescent girls were too small and lost too many participants to follow-up. It also says that these studies only assessed short-term effects and did not follow the participants long-term to determine future impacts on their fertility.

Rather than commission new studies, the FDA evaluated data specific to adolescents extracted from studies that included participants of all ages. The studies the FDA evaluated showed similarly low rates of serious adverse events among adolescents and adults.

Across all of the studies that included adolescents, 21.4% were lost to follow-up. In the same studies, 14.9% of adults were lost to follow-up. The FDA determined that since the numbers were similar between adults and adolescents, adolescents were likely to adhere to the regimen as well as adults and thus could be trusted to take the medicine at home. One study the FDA cited analyzed the characteristics of patients who were lost to follow-up.14 The researchers found that people who lived below the poverty level, whose pregnancies were further along and who were younger than 18 were more likely to be lost.

The studies did not evaluate long-term effects.

The National Academy of Sciences, Engineering, and Medicine reviewed research on future pregnancies in participants after having abortions in 2018 or later.15 They found evidence that prior abortions do not raise the risk of future infertility, pregnancy-related hypertensive disorders (such as preeclampsia), preterm birth, breast cancer or mental health disorders. The authors concluded that there was not enough data to determine whether prior abortions impact future risk of ectopic pregnancies, miscarriages, stillbirths, hemorrhage during a pregnancy or long-term mortality.

7. Abortion Harms Women’s and Girls’ Mental Health.

A 2020 study that followed over 600 women for five years after they had abortions refutes this claim.16 A week after the abortions, only 17% of women reported feeling “mostly negative” emotions about the event. And 12% said they felt both positive and negative emotions. The rest felt neutral or positive about the abortion. After five years, 84% of women reported no emotions or only positive feelings about the abortion. Only 6% reported mostly negative feelings.

While medication abortions are typically safe, the drugs used to induce abortions, mifepristone and misoprostol, come with a small risk of certain side effects, and there are still some things we don’t know about their long-term effects. It’s important to evaluate the potential side effects against the benefits of ending your pregnancy. Your healthcare provider is the best person to help you make the decision that’s best for you.