Objective: The purpose of this study was to determine if cesarean delivery is a risk factor for respiratory distress syndrome (RDS) and if this risk is modified by labor before cesarean.
Study design: This population-based case-control study compared 4778 cases of RDS to 5 times as many controls.
Results: Unadjusted, cesarean delivery was associated with RDS, odds ratio (OR) 3.5 (95% CI 3.2-3.8). After controlling for potential confounding variables, cesarean remained an independent risk factor, OR 2.3 (95% CI 2.1-2.6). Labor modified this risk significantly (P = .02)--with labor, cesarean delivery had an OR of 1.9 (95% CI 2.2-2.9), without labor, the OR was 2.6 (95% CI 1.3-2.8).
Conclusion: Cesarean delivery was an independent risk factor for RDS. The risk was reduced with labor before cesarean, but still elevated. This supports the importance of being certain of fetal lung maturity before cesarean delivery, particularly when done before labor.