Supplementary Material for: Intrauterine inflammation, excessive fetal growth and respiratory morbidities in moderate-to-late preterm neonates

Introduction: Respiratory morbidities in neonates are often progressive and life-threatening, and its early prediction is crucial. Intrauterine inflammation is one of the key control variables of respiratory morbidities in both very preterm and term neonates; however, little is known about its effects in the remaining group of moderate-to-late preterm neonates born between 32+0 and 36+6 weeks gestation. This study aimed to confirm whether intrauterine inflammation is associated with respiratory morbidities in moderate-to-late preterm neonates. Methods: A single-center retrospective observational study was conducted in neonates born between 32+0 and 34+6 weeks gestation between April 2013 and March 2018. The correlation between respiratory morbidities (defined as a requirement for invasive mechanical ventilation longer than the median duration of three days) and intrauterine inflammation was assessed using multivariable logistic regression analysis. Results: The study population comprised 242 neonates born at 33.7 ± 0.8 weeks gestation and weighing 1936 ± 381 g. The multivariable model to predict the outcome comprised respiratory distress syndrome (odds ratio [OR], 9.1; 95% confidence interval [CI], 3.7–22.5; p <0.001), lower gestational age (per week; OR, 0.5; 95% CI, 0.3–0.8; p <0.005), higher birth-weight z-score (OR, 1.6; 95% CI, 1.2–2.2; p <0.005), lower cord blood pH (per 0.10; OR, 0.5; 95% CI, 0.3–0.7; p <0.005), and chorioamnionitis (OR, 2.8; 95% CI, 1.1–7.2; p <0.05). Conclusion: Together with the incidence of respiratory distress syndrome and gestational age, chorioamnionitis and high birth-weight z-scores were associated with an increased incidence of respiratory morbidities in moderate-to-late preterm neonates. The deleterious impact of intrauterine inflammation on the lungs may be common in neonates of virtually all gestational ages. Traditional admission policy of neonatal intensive care units based on a threshold birth-weight, may leave a group of neonates without close observation despite their increased risks for respiratory morbidities.