Date	Event	Description
13 February 2012	Amended	Search updated. Thirty‐seven trial reports added to Studies awaiting classification.
2 September 2008	Amended	Converted to new review format.
31 March 2006	New search has been performed	Search updated in February 2006. New included studies: Brazil 1992; Mexico 1998; Netherlands 2003; Tunisia 2002; South Africa 1997a. New excluded studies: Australia 2002; Bangladesh 2002; Brazil 1984; Brazil 1988; Brazil 1988a; China 2000; Egypt 1989; Egypt 1992; India 1963; India 2001; Italy 2004; Jamaica 1999; Japan 1999; Japan 2000; Japan 2003; Mexico 1967; Mexico 2004; Netherlands 2002; New Zealand 1986; Philipines 2000; South Africa 1984; Venezuela 2001. Study ID changed: South Africa 1994 changed to South Africa 1997b. New ongoing study: Warren 2004a, comparing labetolol with magnesium sulphate. Methods text expanded in line with the guidelines for the Cochrane Pregnancy and Childbirth Group. All text revised and expanded to reflect inclusion, and exclusion, of new studies.