The window of improved neonatal respiratory compliance after rescue antenatal steroids

Objective: To evaluate whether premature infants delivered ≤7 days after rescue antenatal steroid treatment (ideal treatment) have increased passive respiratory compliance compared to those delivered >7 days after treatment (remote treatment). Methods: Secondary analysis of a randomized trial of rescue antenatal steroids on respiratory compliance. Infants in the treatment group were stratified by the interval between rescue antenatal steroids and delivery. We then compared the respiratory compliance in the ideal vs. remote groups. Results: Forty-four women (56 infants) received rescue antenatal steroids. Forty-nine infants had evaluable respiratory compliance measurements, with 27 (GA 30.1 weeks, BW 1362 g) “ideally” treated, and 22 (GA 33.8 weeks, BW 2248 g) “remotely” treated. Respiratory compliance was significantly higher for the ideal compared to the remote group (1.32 vs. 1.06 mL/cm H₂O/kg; p = 0.037). Conclusion: Infants treated with rescue antenatal steroids have a significantly higher respiratory compliance if delivery occurs within 7 days after treatment.