Guidelines from the Royal College of Obstetricians and Gynaecologists describe medication abortion using mifepristone and misoprostol as effective and appropriate at any gestational age.

[23] The World Health Organization and the American College of Obstetricians and Gynecologists recommend mifepristone followed by misoprostol for first- and second-trimester medical abortion.

[6][15] In a Phase III trial, it improved glycemic control, increased insulin sensitivity, and reduced body weight regardless of the cause of CS.

[38] Excessive bleeding and incomplete termination of a pregnancy require further intervention by a doctor (such as a repeat dose of misoprostol or a vacuum aspiration).

A postmarketing summary found, of about 1.52 million women who had received mifepristone until April 2011 in the United States, 14 were reported to have died after application.

Other incidents reported to the FDA included 612 nonlethal hospitalizations, 339 blood transfusions, 48 severe infections, and 2,207 (0.15%) adverse events altogether.

[44][45] Researchers in the United States initiated a trial of the so-called "reversal" regimen in 2019, but stopped prematurely due to serious safety concerns about using mifepristone without follow-up misoprostol.

[46][47] Giving progesterone has not been shown to halt medication abortion, and not completing the combination regimen of mifepristone and misoprostol may cause serious bleeding.

[63][64] In October 1981, Étienne-Émile Baulieu, a consultant to Roussel-Uclaf, arranged tests of its use for medical abortion in 11 women in Switzerland by gynecologist Walter Herrmann at the University of Geneva's Cantonal Hospital, with successful results announced on 19 April 1982.

[63][68] French Health Minister Claude Évin explained: "I could not permit the abortion debate to deprive women of a product that represents medical progress.

[63] Mifegyne was subsequently approved in Great Britain in July 1991,[69] and in Sweden in September 1992,[70] but until his retirement in April 1994, Hoechst AG chairman Wolfgang Hilger, a devout Roman Catholic,[71] blocked any further expansion in availability.

[76] In September 1995, The Population Council licensed mifpristone to Danco Laboratories, which was a new, single-product company that was intended to be resistant to antiabortion boycotts.

[77] In 1996, the US Food and Drug Administration (FDA) conditionally licensed RU-486 for early trimester abortion, pending a resolution on some remaining technical and manufacturing issues.

[76] On 8 April 1997, after buying the remaining 43.5% of Roussel-Uclaf stock in early 1997,[79] Hoechst AG (US$30 (equivalent to $58.28 in 2023) billion annual revenue) announced the end of its manufacture and sale of Mifegyne (US$3.44 (equivalent to $6.68 in 2023) million annual revenue) and the transfer of all rights for medical uses of mifepristone outside of the United States to Exelgyn, a new single-product company immune to antiabortion boycotts, whose CEO was former Roussel-Uclaf CEO Édouard Sakiz.

[80] In 1997, Gideon Richter would withdraw from efforts to manufacture mifepristone in the United States following opposition from pro-life groups, which led to Danco filing a breach of contract lawsuit.

[82] In September 2000 Danco Laboratories, a sub-licencee of the Population Council, received approval from the US Food and Drug Administration (FDA) to sell mifepristone under the brand name Mifeprex.

[101] It is a prescription drug, but was not initially available to the public through pharmacies; its distribution is primarily restricted to specially qualified licensed physicians, sold by Danco Laboratories under the brand name Mifeprex.

Production was intended to begin through the Danco Group in 1996, but they withdrew briefly in 1997 due to a corrupt business partner, delaying availability again.

While the Fourth Circuit had granted a preliminary injunction to allow this distribution, the Supreme Court of the United States issued a stay order in January 2021 to retain the FDA's rule pending the results of the ongoing litigation.

[111] On 16 December 2021, the FDA voluntarily adopted a new rule permanently relaxing the requirement that the pill be obtained in person, allowing it to be sent through the mail.

[122][123] In April 2023, in the FDA v. Alliance for Hippocratic Medicine lawsuit, federal district judge Matthew J. Kacsmaryk issued a preliminary injunction suspending the 2000 approval of mifepristone, which would take effect a week later.

In June 2024, the US Supreme Court unanimously overturned judge Kacsmaryk's Fifth Circuit decision on the grounds that the Alliance for Hippocratic Medicine had no standing to challenge the FDA's regulations of mifepristone.

The first sets forth ways to rush experimental drugs, such as aggressive HIV and cancer treatments, to market when speedy approval is deemed vital to the health of potential patients.

Until December 2021, Mifepristone was approved under the second part of subsection H. The result is that women could not pick the drug up at a pharmacy, but were required to receive it directly from a doctor.

It was approved for use in France in 1988 (initial marketing in 1989), the United Kingdom in 1991, Sweden in 1992, then Austria, Belgium, Denmark, Finland, Germany, Greece, Luxembourg, the Netherlands, Spain, and Switzerland in 1999.

Serbia and Montenegro approved it in 2001,[130] Belarus and Latvia in 2002, Estonia in 2003, Moldova in 2004, Albania and Hungary in 2005, Portugal in 2007, Romania in 2008,[82] Bulgaria, Czech Republic and Slovenia in 2013.

[131] In Italy, clinical trials have been constrained by protocols requiring women be hospitalized for three days, but the drug was finally approved on 30 July 2009 (officialized later in the year), despite strong opposition from the Vatican.

In 2005, a private member's bill was introduced to the Australian Senate to lift the ban and transfer the power of approval to the Therapeutic Goods Administration (TGA).

[144][145] A report from the United States Embassy in Beijing in 2000 said mifepristone had been widely used in Chinese cities for about two years, and that according to press reports, a black market had developed with many women starting to buy it illegally (without a prescription) from private clinics and drugstores for about US$15 (equivalent to $26.54 in 2023), causing Chinese authorities to worry about medical complications from use without physician supervision.

It is only available under medical supervision, not by prescription, due to adverse reactions such as excessive bleeding, and criminal penalties are given for buying or selling it on the black market or over-the-counter at pharmacies.