Characteristics of included, excluded and ongoing studies
The included trials had heterogeneous characteristics and intervention
schemes. The most common doses used were 24 mg of dexamethasone and
betamethasone (Appendix S2 : Table S2.1 ,S2.2 ). The studies were published between 1972 and 2019.
Sixteen studies were conducted in the USA, four in Iran, and two studies
each were conducted in United Kingdom, the Netherlands, Finland, France,
Israel and Brazil. Most studies were conducted in HICs (37), five in
upper MICs and only three in lower MICs (median GNI per capita was
20,170 USD). The sample size varied from 18 to 2,831 women (median 118
women). Membranes were intact, ruptured and mixed (both intact and
ruptured) in 7, 12 and 26 studies, respectively. Regarding the
recruitment gestational age, 30 RCTs set 23-28 weeks as the lower limit
and 33 studies set 34-37 weeks as the upper limit (median gestational
age 30.44 weeks).
Table S2.3 describes the ongoing studies’
characteristics,6,77-79and Table S2.4 the reason of excluded studies initially
included by
full-text80-82).