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picture of a yellow box of medication labeled "Mifeprex (Mifepristone)"

(Photo credit: Anna Moneymaker/Getty Images)

What is Mifepristone?

Mifepristone (MIF-e-PRIS-stone) is an FDA-approved drug that is used for medical termination of pregnancy up to 70 days after the first day of the last period. Mifepristone blocks a hormone called progesterone that is needed for a pregnancy to continue. 

Mifepristone is used together with a second medication called misoprostol (MIS-o-PRO-stol). Misoprostol causes uterine contractions and expels the pregnancy tissue. This combined regimen is recommended as the preferred therapy for medication abortion due to its effectiveness.


Mifepristone may also be used to manage Cushing's syndrome and fibroids.

Mifepristone is used in 96 countries globally and has been used in the U.S. for the past 23 years by over 5 million women for medication abortion.

Studies conducted by the National Institutes of Health (NIH) demonstrated a 97.7% success rate in pregnancy termination with mifepristone, with minimal serious adverse reactions reported. A majority, 99.8% of women who used Mifepristone experienced no serious adverse reactions.

To read more about access to Mifepristone and how the pending Supreme Court ruling may adversely impact access to reproductive healthcare, read the UCSF Mifepristone news brief: The U.S. Supreme Court Weighs Mifepristone for Abortion Care | UC San Francisco (

Speak with your healthcare provider about questions you have about your reproductive health care.


Useful Terms

Cushing Syndrome

Cushing syndrome occurs when the body has an excessive amount of the hormone cortisol for an extended period. Individuals with Cushing syndrome may develop a fatty hump between the shoulders, a rounded face, pink or purple stretch marks on the skin, high blood pressure, bone loss, or type 2 diabetes.

FDA Approved

Uterine Fibroids


“Effectiveness and safety of telehealth medication abortion in the USA.” PubMed, NIH, 15 February 2024, Accessed 23 February 2024.

“Efficacy and safety of medical abortion using mifepristone and buccal misoprostol through 63 days.” PubMed, NIH, Accessed 23 February 2024.

“Medication Abortion Up to 70 Days of Gestation” ACOG, August 14, 2020,, Accessed 27 March 2024.

“Mifepristone (Mifeprex).” MedlinePlus, 15 December 2023, Accessed 22 February 2024.

“Mifepristone (Oral Route) Side Effects.” Mayo Clinic, Accessed 22 February 2024.

“Mifepristone - StatPearls.” NCBI, NIH, Accessed 22 February 2024.

“Questions and Answers on Mifepristone for Medical Termination of Pregnancy Through Ten Weeks Gestation.” FDA, 1 September 2023, Accessed 22 February 2024.

“Updated Mifepristone REMS Requirements.” ACOG, 3 January 2023, Accessed 22 February 2024.



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