The first version of this Cochrane review was published in
1995 (Hodnett 2003), when the first systematic reviews in The
Cochrane Collaboration Pregnancy and Childbirth Group Module
were converted to the Cochrane review format. Thus, a formal
Cochrane protocol was not initially published. Subsequently, the
review author, EllenHodnett, completed a trial of labour support
(Hodnett 2002) with a sample size larger than the entire sample
in the prior version of the original review. As a protection against
bias, she sought co-authors who were blind to the results of the
new trial and who had special expertise that would enhance the
quality of the review. Discussions among the authors led to decisions
to modify the background and methods. The authors decided
that the best approach would be to write a new protocol
for the review. The new protocol was submitted through the peer
review process of the Cochrane Pregnancy and Childbirth Group
and has subsequently evolved into a review that has been updated.