International Variation and Trends of Intraventricular Hemorrhage in Very Preterm Infants

Introduction: We aimed to investigate international variation in gestational age (GA) specific severe intraventricular hemorrhage (IVH) rates, among infants of <30 weeks’ GA from the neonatal networks of 11 high-income countries/region. Methods: Retrospective cohort study of outcomes of grade 3/4 IVH rates and composite of g3/4 IVH or death in GA groups of 22–23, 24–25, 26–27, and 28–29 weeks infants admitted to networks of Australia and New Zealand, Canada, Finland, Israel, Italy (Tuscany), Japan, Spain, Sweden, Switzerland, and the UK. Their risk adjusted trends across 3 epochs (2007-11, 2012-15, and 2016-19) were also evaluated. Results: Outcomes of 165,329 infants (median GA 27 weeks, birthweight 950 g) were analyzed. Overall, the lowest grade 3/4 IVH rate was observed in Japan (6.4%) and the highest in Israel (16.1%). The overall gestation-specific rate of IVH grade 3/4 were 25.8%, 18.6%, 9.0%, and 3.8% and composite outcome of grade 3/4 IVH/death rates 52.2%, 33.6%, 15.6%, and 6.7% for the 22–23, 24–25, 26–27, and 28–29 weeks’ GA groups, respectively. These inter-network variations were greater at lower GA. In epoch comparisons, almost all networks showed significant decreases in GA specific composite outcome rates, particularly in the 26–27 week’ GA group. Japan and Canada demonstrated significant decreases in each GA group while Spain demonstrated significant decreases in each GA group except for 22–23 weeks’ gestation. Conclusions: Rates of grade 3/4 IVH and composite outcome rates varied internationally and have decreased over time. Identification of the driving factors behind variations may allow for opportunities for practice review and improvement.