Mifepristone, which blocks the hormone progesterone, is developed in France. In the coming decades, more than 100 studies will be done on the medication, and all will conclude that it’s safe.

1987: After worldwide clinical trials of more than 20,000 people, mifepristone is shown to be safe and effective when used in combination with another drug, misoprostol, for medication abortions. The French pharmaceutical company that developed the drug seeks approval for use in the country.

1988: Also called RU-486, mifepristone is approved for use in France and China. Medication abortion soon proves to be safer and significantly less expensive than surgical abortion.

1989: The U.S. Food and Drug Administration bans import to the United States.

1992: Leona Benten volunteers to be a legal test case, and is stopped by customs when trying to bring mifepristone to the United States from the U.K., where it was approved the year before. The pills are confiscated. The U.S. Supreme Court rules not to order the return of the medication in a 7-2 decision on a case known as Benten v. Kessler.

1993: In one of his first actions, new U.S. President Bill Clinton directs the FDA to investigate uses of mifepristone on Jan. 22, the 20th anniversary of Roe v. Wade.

1994: The first U.S. clinical trial begins with more than 2,100 participants.

1996: The FDA’s Reproductive Health Drugs Advisory Committee recommends approval of mifepristone, concluding it is safe and effective, and should be made available in the United States.

2000: The FDA approves mifepristone for use in medication abortion up through seven weeks of pregnancy.

2011: The FDA begins requiring a Risk Evaluation and Mitigation Strategy (REMS) for mifepristone, and it can only be administered in a hospital or clinic.

2013: A controlled clinical trial at Columbia University concludes home administration of mifepristone is safe and acceptable.

2015: Arizona is the first state to pass a law requiring physicians to give patients unproven advice that a medication abortion can be “reversed,” despite the lack of supporting medical evidence. At least 14 other states will follow suit.

2016: The FDA extends the window of time a pregnant person can be prescribed mifepristone out to 10 weeks of pregnancy. In changes to the REMS Program, the FDA also requires fewer trips to the doctor during a medication abortion, though some state laws still require a doctor to be present when the pills are taken.

2019: Generic versions of mifepristone are approved by the FDA.

2020: The pandemic hits, but patients must still risk COVID exposure in clinics or hospitals to obtain abortion medication. In May, the American Civil Liberties Union files a federal lawsuit in Maryland requesting that the in-person restrictions be lifted. In July, the court orders the FDA to stop enforcing that requirement temporarily. The medication can be dispensed by mail. More than half of all abortions in 2020 happen by medication.

2021: The FDA under President Joe Biden affirms it will no longer enforce the in-person requirement for distribution of mifepristone in a letter to the American College of Obstetrics and Gynecologists, and the Society for Maternal-Fetal Medicine. By the end of the year, the FDA also says certified pharmacies can distribute mifepristone. But five states have bans on using telemedicine for abortion on the books, and 14 more require clinicians to distribute the drugs in-person.

2022: The Supreme Court rules on June 24 to end federal protections for abortion in Dobbs v. Jackson Women’s Health Organization. Several lawsuits emerge targeting medication abortion. The case known as Alliance for Hippocratic Medicine v. FDA is filed in November challenging the agency’s approval of mifepristone.

2023: 63% of all abortions provided in the U.S. will happen via medication this year, a jump from 2020, research shows.

• January: The FDA permanently removes the in-person requirement from the REMS and adds a new pharmacy certification process. But all eyes are on U.S. District Judge Matthew Joseph Kacsmaryk, appointed to the bench by former President Donald Trump, as he weighs the case in a Texas federal court challenging FDA approval of mifepristone.

• February: 23 attorneys general pen a letter to CVS and Walgreens, expressing support for the retail pharmacies’ sale of mifepristone by mail. Washington Attorney General Bob Ferguson files another federal lawsuit against the FDA, this time arguing that regulations on mifepristone are excessively burdensome and harmful.

• April 7: Kacsmaryk revokes mifepristone’s approval, and the U.S. Department of Justice immediately appeals. On the same day, in a conflicting ruling, a federal judge overseeing the Washington state case orders the FDA to preserve access to mifepristone.

• April 14: U.S. Supreme Court Justice Samuel Alito temporarily blocks any changes to mifepristone regulations, preserving access to the medication for a few more days.

• April 19: Alito again extends the deadline as justices mull whether to pull mifepristone from the U.S. market until they make a decision on the case in its entirety.

• April 21: The Supreme Court decides to maintain mifepristone’s availability, as challenges to Kacsmaryk’s decision are heard in appellate court. Anti-abortion rights activists vow to keep fighting abortion medication, the most common form of abortion post-Dobbs. In some instances, they lean on the Comstock Act of 1873, which bans the mailing of anything considered “obscene,” including abortion-related materials.

• May 6: Colorado becomes the first state to ban abortion ‘reversals.’ The law withstands the state regulatory board but is later blocked by a federal judge.

• Aug. 16: A federal appeals court decides that mifepristone should stay on the market but that the U.S. should revert to pre-2016 rules, which would mean in-person doctor visits, only allowing doctors to prescribe the drug and limiting use at seven-weeks gestation instead of 10. But the decision doesn’t take effect because it’s immediately stayed until the Supreme Court decides whether to take the case.

• Dec. 13: The U.S. Supreme Court agrees to hear FDA v. Alliance for Hippocratic Medicine.

2024: Early in the year, legal briefs backing abortion medication access flood the court. Dozens more are also filed encouraging justices to restrict access to abortion medication and return to pre-2016 regulations.

• Feb. 5: Sage Publishing retracts several studies key in the arguments against mifepristone, citing undeclared conflicts of interest and unreliable findings.

• Feb. 27: Researchers publish a commentary in a medical journal calling for the retraction of four more abortion-related studies central in legal arguments to restrict reproductive rights.

• March 26: The U.S. Supreme Court hears arguments about curbing mifepristone’s use and availability. A decision is expected in the summer.