How effective is medication abortion at terminating a pregnancy?

Medication abortion regimens can be safely and effectively during early pregnancy. For all three methods of medication abortion, efficacy decreases with increasing gestational age. The mifepristone and misoprostol regimen is the most effective (95%-98%) and can be used throughout the first nine weeks of pregnancy. The methotrexate and misoprostol regimen is highly effective in the first seven weeks of pregnancy (95%) but is less effective after 49 days (82% during the eighth week of pregnancy). The efficacy of misoprostol alone is variable and depends on both gestational age and regimen (65%-93%).

The most recent studies on the use of misoprostol alone for early pregnancy termination suggest an efficacy rate of 75%-85%. This efficacy is based on the vaginal administration of 800 micrograms of misoprostol followed 24 hours later with another 800 micrograms (vaginal).

If you have questions about medication abortion, please visit our page on frequently asked questions.

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Last updated: September 2009