Date	Event	Description
15 October 2013	Amended	Amendments made to the 'Risk of bias' tables and minor data errors corrected. Outcomes reordered to reflect clinical importance.
23 November 2012	New search has been performed	Searches re‐run. Four new trials included and one new trial excluded. Conclusions unchanged.
23 November 2012	New citation required but conclusions have not changed	Review updated. Four new trials included and one new trial excluded. Conclusions unchanged.
30 November 2011	Feedback has been incorporated	Feedback addressed.
30 November 2011	New search has been performed	Review updated, searches rerun. Two new trials included, one being a large RCT with fondaparinux.
30 November 2011	New citation required and conclusions have changed	Review updated. Conclusions changed.
27 October 2010	Feedback has been incorporated	Feedback added
26 April 2010	Amended	Contact details updated
1 September 2008	Amended	Converted to new review format.
19 February 2007	New citation required and minor changes	Updated to correct error in citation. Searches re‐run and no new trials found.