mifepristone

American

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

noun

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

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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of mifepristone

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

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Medication management, such as mifepristone plus misoprostol and a D&C are also used for terminating unwanted pregnancies.

From Salon • May 26, 2026

The misoprostol-only protocol has some downsides: It can be a bit more unpredictable, since it can take longer for a body to expel a pregnancy if it’s not prepped with mifepristone.

From Slate • May 18, 2026

The FDA has said it is reviewing the guidelines around mifepristone.

From The Wall Street Journal • May 14, 2026

The disparity was stark for ectopic pregnancy: The data indicate that the inappropriate provision of mifepristone to a woman with an ectopic pregnancy was between three and six times more likely with remote dispensing.

From The Wall Street Journal • May 10, 2026

The two-drug protocol is also used to manage miscarriage, but Brandi fears the legal wrangling over mifepristone is creating "stigma."

From Barron's • May 10, 2026

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023