Poor postdischarge head growth is related to a 10% lower intelligence quotient in very preterm infants at the chronological age of five years.

Abstract

This study examined the relationship between head growth and cognitive outcome at the age of five years in preterm infants born at less than 32 weeks of gestation from 2003 to 2009, as previous research has mostly focused on outcomes in toddlers. The head circumference of 273 very preterm infants born in Tyrol, Austria, was measured at birth, discharge, the corrected ages of three, 12 and 24 months and the chronological age of five years. Suboptimal head size was defined as a head circumference of more than one standard deviation below the mean. Full-scale intelligence quotient (IQ) at five years was determined using Wechsler Preschool and Primary Scales of Intelligence, third edition. Infants with a suboptimal head size at the age of three months had a significantly lower median IQ than those with a normal head size (90 [20-122] versus 98 [20-138], p = 0.001) and from three months onwards they were more likely to exhibit cognitive delay. A suboptimal head size from the age of three months was consistently related to a 10% lower IQ, and this study adds further evidence that head growth failure, especially during the early postdischarge period, is related to impaired cognitive abilities.