Date	Event	Description
19 December 2018	Amended	We are reverting to the original content as changes were made without a new citation version.
25 July 2017	New citation required and conclusions have changed	The addition of 15 new trials and application of Cochrane methods led to a change in the conclusions of this review
7 March 2017	New search has been performed	The number of included studies in this updated review increased to 115. The search was updated to February 2017. In this update, we assessed all the included studies for risk of bias using the Cochrane 'Risk of bias' tool, and completed 'Risk of bias' tables. We graded major outcomes and comparisons of this review following GRADEpro GDT 2014 guidelines. These two processes changed our conclusions.
15 February 2012	New citation required and conclusions have changed	The number of included studies in this updated review increased from 81 to 100. Compared with levonorgestrel, the risk ratio of pregnancy with mid‐dose (25 mg‐50 mg) mifepristone was slightly increased from 0.50 (95% CI 0.32 to 0.79) to 0.64 (95% CI 0.45 to 0.92) in this update. Ulipristal acetate appeared more effective than levonorgestrel, but more data are needed to confirm this association. Ulipristal acetate users were more likely to experience a menstrual return after the expected date than levonorgestrel users did. However, levonorgestrel was associated with higher risk of early menstrual return than ulipristal acetate. Gestrinone was included in this review for the first time. It appeared to have similar effectiveness and overall side effects as mifepristone. The latter was associated with higher risk of menstrual delay than gestrinone.
18 February 2008	New citation required and conclusions have changed	Substantive amendment