Increased neonatal morbidity despite pulmonary maturity for deliveries occurring before 39 weeks

Objective: To compare neonatal outcomes following deliveries <39 weeks after confirmation of fetal lung maturity with scheduled deliveries >= 39 weeks. Methods: A retrospective cohort study examining neonatal outcomes of women who were delivered following documented fetal pulmonary maturity at 36, 37, and 38 weeks compared to women undergoing a scheduled delivery at 39, 40, and 41 weeks. The X-2-test and Student's t-test were used to compare categorical and continuous data, respectively. Results: Delivery prior to 39 weeks following fetal pulmonary maturity was associated with a 8.4% composite neonatal morbidity rate as compared to 3.3% for deliveries at 39 weeks or greater (relative risk [RR] 2.9; confidence interval [CI] 2.4-3.6). Neonatal respiratory morbidity was significantly higher (5.4%) for those delivering at less than 39 weeks with documented fetal pulmonary maturity as compared to 2.1% for those delivering at 39 weeks or greater (RR 3.0; CI 2.3-3.9). Increased neonatal morbidity persisted for those delivered prior to 39 weeks even after excluding all diabetics (p < 0.001). Significant increases in neonatal morbidity were noted for deliveries prior to 39 weeks regardless of the mode of delivery. Conclusion: Despite fetal pulmonary maturity, delivery before 39 weeks is associated with significantly increased neonatal morbidity when compared to scheduled deliveries at 39 weeks or greater.