mifepristone

American  

[mif-uh-pris-tohn] / ˌmɪf əˈprɪs toʊn /

noun

1. an antigestational drug, C 29 H 35 NO 2 , that prevents a fertilized egg from attaching to the uterine wall by blocking the action of progesterone.

---

mifepristone British  

/ mɪˈfɛprɪˌstəʊn /

noun

1. an antiprogestogenic steroid, used in the medical termination of pregnancy. Formula: C 29 H 35 NO 2

---

Etymology

Origin of mifepristone

1985–90; probably alteration of (a)mi(no)phe(nol) + pr(opyl) + est(radiol) + -one

Example Sentences

See Examples For:

mifepristone

He also noted that mifepristone was not included among nearly 700 pharmaceutical compounds the EPA previously screened for potential water contamination concerns.

From Salon ● Jul. 6, 2026

She said proposals to test wastewater for mifepristone raise concerns about how such monitoring data could eventually be used and whether it could increase scrutiny of people who obtain medication abortions.

From Salon ● Jul. 6, 2026

Former FDA Commissioner Marty Makary, ousted last month, had promised lawmakers he would launch a mifepristone study but told others in the administration that he needed new data systems for the effort.

From The Wall Street Journal ● Jun. 5, 2026

A lower court in Louisiana also required the FDA to give an update by October on a promised review of the safety regulations governing mifepristone.

From The Wall Street Journal ● Jun. 5, 2026

Taking misoprostol alone has also become a standard treatment for unwanted pregnancies in countries where mifepristone is harder to come by.

From Slate ● May 18, 2026