Comment: The quality of evidence is downgraded by study limitations (unclear allocation concealment in 2 trials and unclear blinding in one trial).
A Cochrane review (abstract , review ) included 10 studies with over 4 730 women and 5 650 babies. Treatment of women who remain at risk of preterm birth (before 34 weeks' gestation) 7 or more days after an initial course of prenatal corticosteroids with repeat dose(s) of corticosteroid reduced the risk of neonate respiratory distress syndrome (RDS) (RR 0.83, 95% CI 0.75 to 0.91; 8 trials, 3206 infants, numbers needed to treat (NNT) 17, 95% CI 11 to 32) and serious infant morbidity (RR 0.84, 95% CI 0.75 to 0.94; 7 trials, 5094 infants, NNT 30, 95% CI 19 to 79)Treatment with repeat dose(s) of corticosteroid was associated with a reduction in mean birthweight (mean difference (MD) -75.79 g, 95% CI -117.63 to -33.96; 9 trials, 5626 infants). However, outcomes that adjusted birthweight for gestational age (birthweight Z scores, birthweight multiples of the median and small-for-gestational age) did not differ between treatment groups. At early childhood follow-up no statistically significant differences were seen for infants exposed to repeat prenatal corticosteroids compared with unexposed infants for the primary outcomes (total deaths; survival free of any disability or major disability; disability; or serious outcome) or in the secondary outcome growth assessments.