Risk factors associated with respiratory disorders in late preterm infants

Objective: Late preterm infants are still high risk for respiratory problems. The aim of this study was to identify risk factors associated with respiratory problems in Japanese late preterm infants.Methods: In this retrospective multicenter study, we included singleton late preterm deliveries at 34+(0/7)-36+(6/7) weeks of gestation. We excluded cases with congenital anomalies. We defined neonatal respiratory disorders (NRD) as the combination of the need for mechanical ventilation or the use of nasal continuous positive airway pressure. We examined the perinatal risk factors associated with NRD.Results: We included 683 late preterm infants. We found that 13.7%, 6.8% and 2.6% of the infants with NRD were born at 34, 35 and 36 weeks of gestation, respectively. In a multivariate logistic regression analysis adjusting for confounders, the gestational age (GA) at birth (adjusted odds ratio 0.40 per week [95% confidence interval, 0.25-0.61]), cesarean birth (4.18 [2.11-8.84]), and a low Apgar score (33.3 [9.93-121.3]) were independent risk factors associated with NRD.Conclusions: An earlier GA, cesarean delivery, and a low Apgar score are independent risk factors associated with NRD in singleton late preterm infants. Patients with late preterm deliveries exhibiting these risk factors should be managed in the intensive delivery setting.