Respiratory Morbidities in Newborn Infants by Gestational Age Following Elective Cesarean Section beyond 35 Weeks of Gestation

Purpose: We evaluate respiratory morbidities in infants beyond 35 weeks of gestation born via elective cesarean section by gestational age. Methods: This is a retrospective study of 443 infants who were born at Seoul National University Hospital by elective cesarean section beyond 35 weeks of gestation from January 2011 to December 2012. We compared respiratory morbidities in four groups classified by gestational age (35+0-36+6 weeks, 37+0-37+6 weeks, 38+0-38+6 weeks, 39+0-40+6 weeks). Results: There were significantly lower Apgar scores in the late-preterm infant group (35-36 weeks) compared to other term infant groups and the proportion of infants born from mothers with preeclampsia gradually decreased as gestational age increased. There were significant differences in O2 supplement, duration of O2 (>24 hours), checked chest radiography, transient tachypnea of newborn (TTN), transfer to neonatal intensive care unit (NICU), endotracheal intubation, and ventilator uses including nasal continuous positive airway pressure in four groups (P<0.05). By logistic regression analysis, compared to births at 38 weeks, births at 35-36 weeks and at 37 weeks were associated with an increased risk of respiratory morbidities [odds ratios (OR) and 95% confidence intervals (CI) for births at 35-36 weeks, 122.5 (17.4-863.4) for TTN; 54.0 (10.1-289.4) for transfe