Dynamic changes in postnatal growth predict adolescent mental health problems in survivors of extremely low birth weight (ELBW).

Although individuals born at extremely low birth weight (ELBW; ≤1000 g) are known to be at greater risk for mental health problems than individuals born at normal birth weight (NBW; ≥2500 g), contributions of postnatal growth to these relations have not been fully explored. We compared individual differences in the Ponderal Index [(PI; weight(kg)/height(m³)] and head circumference (HC) in predicting internalizing and externalizing behaviors in childhood and adolescence in a cohort of ELBW survivors (N = 137) prospectively followed since birth. Baseline models indicated that infants who were born thinner or with smaller HC showed greater PI or HC growth in the first 3 years. Latent difference score (LDS) models showed that compensatory HC growth in the first year (ΔHC = 20.72 cm), controlled for birth HC, predicted ADHD behaviors in adolescence in those born with smaller HC. LDS models also indicated that the PI increased within the first year (ΔPI = 1.568) but decreased overall between birth and age 3 years (net ΔPI = -4.597). Modeling further showed that larger increases in the PI in the first year and smaller net decreases over 3 years predicted more internalizing behaviors in adolescence. These findings suggest early growth patterns prioritizing weight over height may have negative effects on later mental health in ELBW survivors, consistent with developmental programming theories.