Delivery room intubation and severe intraventricular hemorrhage in extremely preterm infants without low Apgar scores: A Japanese retrospective cohort study

The purpose of this study was to assess the associations between delivery room intubation (DRI) and severe intraventricular hemorrhage (IVH), as well as other neonatal outcomes, among extremely preterm infants without low Apgar scores using data from a large-scale neonatal registry data in Japan. We analyzed data for infants born at 24-27 gestational weeks between 2003 and 2019 in Japan using robust Poisson regression. Infants with low Apgar scores (<= 1 at 1 min or <= 3 at 5 min) were excluded. The primary outcome was severe IVH. Secondary outcomes were other neonatal morbidities and mortality. The full cohort included 16,081 infants (intubation cohort, 13,367; no intubation cohort, 2714). The rate of DRI increased over time (78.6%, 2003-2008; 83.4%, 2009-2014; 87.8%, 2015-2019), while the rate of severe IVH decreased (7.1%, 2003-2008; 5.7%, 2009-2014; 5.3%, 2015-2019). Infants with DRI had a higher risk of severe IVH than those without DRI (6.8% vs. 2.3%; adjusted risk ratio, 1.86; 95% confidence interval, 1.33-2.58). The results did not change substantially when stratified by gestational age. Despite conflicting changes over time in DRI and severe IVH, DRI was associated with an increased risk of severe IVH among extremely preterm infants in Japan.