How late in a pregnancy can medical abortion be used? How early?

The World Health Organization has published evidence that suggests that misoprostol alone, or in combination with mifepristone, are safe and effective through 12 weeks of pregnancy. After 12 weeks, it is recommended they are used under clinical care, as there is a higher chance of a complication and the medicines are used differently. Please see the WHO guidelines for information.^1, 2

How early in the pregnancy can a medical abortion be done?

Medical abortion can be used from very early on in pregnancy, as soon as a woman misses her period and confirms the pregnancy. Since there is no research about medical abortion efficacy when used before a woman misses her period it is advisable that women use medical abortion pills only after she misses her period.