The individualized reference had higher specificity and PPV in predicting poor neurodevelopment. Neonates defined as SGA by the individualized reference alone had a higher risk (RR=2.20, 95% CI: 1.20, 4.00) of poor cognitive outcome, while those identified by the ultrasound-based reference alone did not (RR=0.95, 95% CI: 0.45, 2.01). None of the references could predict poor neurodevelopment well at age five.