ABSTRACT
OBJECTIVES: The current study examined the effect of birth weight on the relationship between age and IQ of children, who were born preterm with very low birth weight (VLBW) or extremely low birth weight (ELBW). METHODS: The study subjects were 82 children, aged between 3–5 years, who visited the neonatal intensive care unit of a university hospital located in Seoul. The children had been born prematurely with VLBW or ELBW. Their IQ was tested using the performed Korean-Wechsler Preschool and Primary Scale of Intelligence fourth edition. RESULTS: A hierarchical regression analysis showed a significant interaction effect of birth weight and age on Full Scale IQ (FSIQ); the effect of age on FSIQ differed according to birth weight. For the group with VLBW, FSIQ was more likely to be higher with increasing age. Conversely, for the group with ELBW, FSIQ remained low regardless of the age level. In addition, birth weight and age had a significant interaction effect on the Visual Spatial Index. Birth weight had a significant main effect on Verbal Comprehension Index. CONCLUSION: This research suggested the possibility of predicting the cognitive developmental of premature children, by highlighting the fact that prematurely born children, with VLBW/ELBW, have different cognitive developmental trajectories.