Antenatal corticosteroids after 34 weeks' gestation: Do we have the evidence?

There is evidence to support the use of antenatal corticosteroids prior to late preterm birth at 35+0 to 36+6 weeks' gestation and for specific 'at-risk' populations, such as planned cesarean section birth and infants of women with diabetes in pregnancy, to reduce short-term neonatal respiratory morbidity. However, the overall size of effect at late preterm and term gestational ages is less than for early and moderate preterm birth and should be countered against the potential harms. Evidence from randomized trials suggest an increase in the incidence of neonatal hypoglycemia after corticosteroid use prior to late preterm birth; any effect of antenatal corticosteroids on neonatal glycemic control after planned cesarean section birth or for infants born to mothers with diabetes in pregnancy is unknown. Accumulating evidence suggests neonatal hypoglycemia may adversely affect childhood development. To date, no trials of antenatal corticosteroids after 34 weeks' gestation have reliably assessed outcomes beyond the neonatal period.