Is there a time period within which woman can take mifepristone?

Mifepristone is a medication used to end a pregnancy. It is most effective when taken within 10 weeks of the first day of the last menstrual period. Mifepristone can be taken up to 70 days (10 weeks) after the first day of the last menstrual period. However, it is most effective when taken as early as possible in pregnancy.