Postnatal weight loss and neurodevelopmental outcomes at age 3 years in extremely preterm infants: a cohort study

Abstract Background Previous research has suggested a correlation between postnatal maximum weight loss (MWL) and both neonatal mortality and morbidities in extremely preterm infants. However, the relationship between MWL and neurodevelopmental outcomes remains underexplored. Methods In a single-center, retrospective cohort study at Okayama Medical Center, we evaluated data from extremely preterm infants admitted to the neonatal intensive care unit from 2010 to 2020. Infants who died within the first 10 days of life were excluded. MWL in the first 10 days was the main exposure, categorized into three groups: >15%, 5–15%, and 15% MWL group, 71 in the 5–15% group, and 24 in the 15% MWL; 26.1 weeks and 818 g for 5–15% MWL; and 26.0 weeks and 734 g for 15% (RR 1.32, 95% CI 1.00–1.75) and