Search strategy
We conducted a literature search strategy without language
restriction. We updated the exhaustive searches of the previous Cochrane
reviews9,10from the oldest search date reported in
Brownfoot 20139(February 13, 2013) until October 2019, in PubMed MEDLINE,
EMBASE, LILACS, Cochrane Library, Clinical Trials.gov and the
International Clinical Trials Registry Platform (ICTRP) for ongoing
trials search. The MeSH search terms included premature birth,
betamethasone, dexamethasone and glucocorticoids (Full search strategy
in Appendix S1 ). We also searched references of included
studies and contacted experts for additional evidence.