The last search update was performed on 20 May 2014. Bibliographies from relevant studies were reviewed, and authors of potentially eligible studies were contacted when necessary to request further information regarding study design or primary outcomes.
Studies were eligible if they fulfilled all the following: (1) they were randomized controlled trials; (2) subjects were women
with gestational diabetes requiring drug treatment; (3) they compared glibenclamide with insulin, metformin with insulin,
or metformin with glibenclamide; (4) they provided information on one or more maternal or fetal outcome; and (5) they were published as a full paper. The exclusion criterion was a significant overlap with other articles by the same group.