The Association of Respiratory Morbidity and Assisted Ventilation Rates in Late Preterm Births after Premature Rupture of Membranes: A Retrospective Cohort Study in a Tertiary Center

Abstract

Objective: The aim of this study was to determine the association of respiratory morbidity and assisted ventilation rates in late preterm births after premature rupture of membranes (PROM). Methods: This retrospective cohort study included 584 consecutive women admitting due to PROM and delivered between 34+0 and 36+6 weeks of gestation at Seoul National University Bundang Hospital from August 2008 to July 2018. Multifetal pregnancies and intrauterine fetal demise were excluded. Primary outcome included the use of assisted ventilation and neonatal respiratory complications and a multivariable analysis was also performed. Results: 1) The proportions of neonates receiving assisted ventilation were significantly decreased as the gestational age at delivery advanced (P-trend <0.05 for all) in late preterm births after PROM. 2) The incidences of respiratory distress syndrome were 14%, 7%, and 3% for preterm births in the 34th, 35th, and 36th week of gestation (P-trend=0.007), respectively. 3) The gestational age at delivery was associated with the rates of positive pressure ventilation immediately after birth, neonatal intensive care unit (NICU) admission, minor assisted ventilators in preterm births with PROM after 34 weeks of gestation when analyzed by multivariate logistic regression. 4) The interval from PROM to delivery was independently associated with the rate of NICU admission (odds ratio, 1.04; 95% confidence interval, 1.01-1.06). Conclusion: Although late preterm births seem to be less severe than earlier gestation, gestational age at delivery is still an important factor for neonatal respiratory complications and for the use of assisted ventilation, even when the pregnancy is complicated with PROM.