The effect of a single remote course versus weekly courses of antenatal corticosteroids on functional residual capacity in preterm infants: A randomized trial

Objective. There are no randomized data on the effect of repeat courses of corticosteroids during pregnancy on newborn pulmonary function. Our objective was to compare the effect of a single remote course of antenatal steroids (AS) with weekly courses of AS on functional residual capacity (FRC) and respiratory compliance in preterm infants. Study Design/Methods: Pregnant women 25 to 33 weeks' gestation, who remained undelivered 1 week after their first course of antenatal corticosteroids (two 12-mg doses of betamethasone) were randomized to weekly courses of corticosteroids versus weekly placebo until delivery or 34 weeks' gestation. FRC was measured with the nitrogen washout technique and respiratory compliance with the single breath occlusion technique within 48 hours of life. Results. Thirty-seven infants (mean gestational age at delivery ∼32.5 weeks) were studied. Maternal and infant demographics were similar. There was no significant difference in FRC (28.5 vs 27.5 mL/kg) or respiratory compliance between the infants who received a single remote course of antenatal corticosteroids and those who received weekly courses of corticosteroids until delivery. There was no significant difference in admission head circumference or birth weights between the groups. Conclusions. Our results demonstrate that weekly repetitive courses of AS do not significantly increase FRC or respiratory compliance in preterm infants when compared with a single remote course of steroids given at a mean gestational age of 29 weeks.