Antenatal and Postnatal Growth and 5-Year Cognitive Outcome in Very Preterm Infants

Abstract

To study how antenatal growth affects cognitive outcome in very preterm infants and to determine whether there is an association between growth in any particular time period between birth and 5 years of age and cognitive outcome. Small for gestational age (SGA) and non-SGA infants were analyzed separately, because antenatal growth may affect postnatal growth. Very low birth weight (<1501 g) infants born between 2001 and 2006 and infants born at <32 gestational weeks between 2004 and 2006 who were treated at Turku University Hospital (n = 181) were followed. Weight, length, and head circumference (HC) of the infants were measured at 9 time points between birth and 5 years. The growth was determined as a z score change between measurement points. Cognitive development was assessed at 5 years of age with the Wechsler Preschool and Primary Scales of Intelligence-Revised. The association between growth and full-scale IQ (FSIQ) was studied. Growth in length and height was not associated with 5-year cognitive outcome. However, weight (r = 0.18, P = .04) and HC growth (r = 0.25, P = .01) between birth and 2 years of corrected age correlated to FSIQ in non-SGA children. In SGA children, HC growth (r = 0.33, P = .03) around term age correlated to FSIQ. Cognitive outcome was similar in SGA and non-SGA very preterm infants. Growth affected cognition positively in both subgroups, but the critical time period was different.