Risk Assessment of Cognitive Impairment at 2 Years of Age in Infants Born Extremely Preterm Using the INTERGROWTH-21st Growth Standards.

Objective: To assess the risk of cognitive impairment among infants born extremely preterm using the INTERGROWTH-21st standards.

Study Design: We analyzed anthropometric data at birth and 36 weeks postmenstrual age (PMA) from infants born extremely preterm (24-26 weeks of gestation) admitted to US neonatal units between 2008 and 2018. To determine INTERGROWTH-21st z-score values that indicate an increased risk of cognitive impairment at 2 years of age (Bayley cognitive score <85), we employed classification and regression trees and redefined growth failure (weight, length, and head circumference z-scores at 36 weeks PMA) and growth faltering (weight, length, and head circumference z-score declines from birth to 36 weeks PMA).