Association of Postnatal Growth Changes and Neurodevelopmental Outcomes in Preterm Neonates of <29 Weeks' Gestation

To examine associations between weight and head circumference (HC) changes and neurodevelopment in preterm infants.

This retrospective cohort study of Canadian Neonatal Network and Canadian Neonatal Follow-Up Network sites included preterm infants born 2010-2018. Logistic regression and model diagnostics evaluated relationships between changes in z score and velocity of weight and HC from birth to discharge from a tertiary neonatal intensive care unit, discharge to 18-24 months corrected age (CA), and birth to 18-24 months CA and significant cognitive/motor impairment at 18-24 months CA classified using a Bayley Scales of Infant and Toddler Development-Third Edition cognitive or motor composite score <70.

In total, 4530 infants (53.0% male) with a mean (SD) gestational age of 26.3 (1.4) weeks and birth weight of 920 (227) g were included. Weight and HC changes were associated with lower odds of significant cognitive/motor impairment including an OR of 0.87 (95% CI: 0.83, 0.91; P < .001) for a 1-g/d increase in weight from discharge to 18-24 months CA and 0.81 (95% CI: 0.75, 0.88; P < .001) for a 1-unit increase in HC z score from birth to 18-24 months CA. Associations were not statistically significant in morbidity-free neonates. Weight and HC gains poorly discriminated between infants with and without significant cognitive/motor impairment (areas under the receiver operating characteristic curve of <0.64). No growth measure had a clinically useful balance of sensitivity and specificity.

Weight and HC changes were associated with significant cognitive/motor impairment but had poor discriminatory capability. Neonatal morbidities may make a larger contribution than postnatal growth to neurodevelopment.