Severe brain injury and trends of gestational‐age‐related neurodevelopmental outcomes in infants born very preterm: A population cohort study

Aim To investigate the impact of severe neonatal brain injury (SNBI) on gestational age‐related trends in neurodevelopmental impairment (NDI) outcome in infants born very preterm. Method A population‐based cohort study recruited 1091 infants born at a gestational age of less than 31 weeks between 2011 and 2020. The trends in neonatal morbidities, mortality, and 24‐month NDI severity (no/mild, moderate, severe) by epoch (2011–2015, 2016–2020) and gestational age (22–25 weeks, 26–28 weeks, 29–30 weeks) were determined in infants with and without SNBI inclusion. Results There was increased antenatal steroid use and higher maternal education and socioeconomic status over time. The rates of neonatal morbidities and mortality had no temporal changes. Among 825 infants with follow‐up, those in the 22 to 25 weeks gestational age group had declining trends in cerebral palsy and severe cognitive impairment, with decreased rates of severe NDI from 19% to 8% across epochs, particularly in those without SNBI (from 16% to 2%). Relative to its occurrence in epoch 2011 to 2015, risk of severe NDI was significantly reduced in epoch 2016 to 2020 (adjusted relative risk 0.39, 95% confidence interval 0.16–0.96) for infants born at 22 to 25 weeks gestational age, and the risk dropped even lower in these infants without SNBI (0.12, 0.02–0.84). Interpretation Infants born at 22 to 25 weeks gestational age had decreased rates of severe NDI in the decade between 2011 and 2020, particularly those without SNBI. The improvement might be attributed to better perinatal/neonatal and after‐discharge care. The 24‐month neurodevelopmental impairment (NDI) outcomes by gestational age (22–25 weeks, 26–28 weeks, 29–30 weeks) and epoch (2011–2015, 2016–2020) were investigated in infants born preterm with and without inclusion of severe neonatal brain injury (SNBI). Infants in the 22 to 25 weeks gestational age group had decreased severe NDI rates from 19% to 8% across epochs, particularly those without SNBI (from 16%–2%). Infants in the 26 to 28 weeks and 29 to 30 weeks gestational age groups had no temporal changes in the distribution of NDI severity with or without SNBI inclusion. Plain language summary: https://onlinelibrary.wiley.com/doi/10.1111/dmcn.16062 This original article is commented by Morgan on pages 8–9 of this issue.