Infants born small-for-gestational age (SGA) are at increased risk of developmental difficulties. Identifying those most at risk is challenging. We examined the effect of neonatal body composition and customised birthweight centiles on neurocognitive and behavioural outcomes at age 2.Study design
Prospective cohort study of term infants from the Cork BASELINE Birth Cohort Study classified into the following exposure groups: a birth weight <10th customised centile (SGA, n=51); body fat percentage at birth <10th centile (thin-for-gestational age (TGA, n=51)) or both SGA and TGA infants (small- and thin-for-gestational age (STGA), n=13). The SGA, TGA and STGA groups were compared with a reference (unexposed) group of appropriate-for-gestational age (AGA, n=189) infants. Outcome was assessed at 24 months using the Bayley Scales of Infant Development Version III and the Child Behaviour Checklist.Results
Outcomes in the SGA infants did not differ significantly from the AGA group. TGA infants had significantly lower scores across all three domains, with a 0.35, 0.38 and 0.41 SD reduction in language, cognitive and motor scale scores, respectively. STGA infants had poorer cognitive outcome with a median cognitive scale score of 90 (IQR 85–95) compared with 95 (IQR 90–100) in the AGA reference group, p=0.005. The adjusted OR of developmental delay at 2 years was 5.00 (95% CI 1.46 to 17.13, p=0.010) in the STGA group.Conclusion
TGA infants, in particular those born STGA, are at increased risk of developmental delay at 2 years compared with the AGA infants.