Date	Event	Description
29 March 2019	New citation required but conclusions have not changed	Three new studies added, no changes to conclusions.
7 December 2018	New search has been performed	Searches updated 18 July 2018 and three new included trials added (Batra 2013; Dickson‐Spillmann 2013; Hasan 2014). Comparisons reorganized. Change of authorship: J Hartmann‐Boyce added.
22 July 2010	New citation required but conclusions have not changed	Change of authorship: N Abbott & A White removed; H McRobbie, N Walker, M Mehta added.
22 July 2010	New search has been performed	Updated with two new trials (Elkins 2006, Carmody 2008). Comparisons reorganised. No major change to conclusions.
19 June 2008	Amended	Converted to new review format.
22 May 2005	Amended	Response to Feedback included
16 February 2005	Amended	Response to Feedback included
16 February 2005	New search has been performed	Updated for 2005 Issue 2. Four references added to Excluded studies (Bastien 1983, Casmar 2003, Frank 1986, Richard 2002)
5 August 2001	New search has been performed	Updated for 2001 Issue 4. No new studies identified.