Cognitive Outcomes of Children with Very Low Birth Weight at 3 to 5 Years of Age

BACKGROUND: The cognitive consequences and risk factors based long-term outcome of very-low-birth-weight (VLBW; < 1,500 g) infants in Korea has not been studied. The aim of this study was to determine the influence of perinatal and neonatal risk factors on the cognitive performance of VLBW children at 3 to 5 years of age. METHODS: We enrolled 88 VLBW infants without cystic periventricular leukomalacia for the assessment of their demographic data, cognitive performance, and development of cerebral palsy (CP) at 3 to 5 years of age. Cognitive performance was assessed using the Korean version of the Wechsler Preschool and Primary Scale of Intelligence IV. Growth data were assessed with measurements of weight, height, and head circumference (HC) at the corrected ages of 6, 12, and 18 months, and 3 to 5 years of age. RESULTS: In the VLBW group, the full-scale intelligence quotient (FSIQ) was 96.1 ± 15.2 at the mean age of 4.5 years. The incidence rate of CP was 3.4%. Overall, 17% (15/88) of the VLBW children had a below-average FSIQ (< 85). We divided the VLBW children into the abnormal FSIQ group (< 85, n = 15) and the normal FSIQ group (≥ 85, n = 73). VLBW children with intrauterine growth retardation (IUGR) was associated with a below-average FSIQ at the mean age of 4.5 years (< 85, 8/15, 53.3% vs. ≥ 85, 5/73, 6.8%; P < 0.001). After controlling for associated clinical factors, IUGR in the VLBW children was found to be associated with an abnormal FSIQ at the mean age of 4.5 years (P = 0.025). The weight, height, and HC obtained for both groups showed that normal growth was maintained at the mean age of 4.5 years with no significant difference between abnormal and normal FSIQ groups. CONCLUSION: Fifteen of 88 (17%) of the VLBW children had a below-average FSIQ (< 85). VLBW with IUGR is associated with poor cognitive outcomes at the mean age of 4.5 years.