Abstract
AIM: The aim of the study was to investigate cognitive outcomes at 6.5 years in children born very preterm, in relation to neonatal characteristics and 2.5-year neurodevelopment. METHODS: A prospective cohort, with gestational age 22.3-31.9 weeks, born 2004-2007, were examined at 2.5 years with the Bayley Scales of Infant and Toddler Development (Bayley-III) (n = 100) and at 6.5 years with the Wechsler Intelligence Scales (n = 91). RESULTS: Neonatal factors independently related to 6.5-year outcome were gestational age, retinopathy of prematurity and treated persistent ductus arteriosus. The Bayley-III cognitive scores explained only 44% of the Full-Scale Intelligence Quotient result at 6.5 years, and 22% of the children had Wechsler index results below -1 SD, indicating cognitive impairment, after average test results at 2.5 years. The relative risk to score below -1 SD on the Full-Scale IQ was 2.83 (95% CI 1.45-5.53) in children with gestational age below 28 weeks and 2.22 (95% CI 1.18-4.17) at gestational age 28-31 weeks. CONCLUSION: Very preterm infants born in the 2000s had increased risks for impaired cognition at 6.5 years, but individual predictions based on neonatal risks and 2.5-year test results were not enough to identify all high-risk children.