(HealthDay News) – Gains in neonatal weight and head circumference in the first four weeks of life correlate with children’s IQ at early school-age, according to a study published online June 17 in Pediatrics.

Lisa G. Smithers, PhD, from the University of Adelaide in Australia, and colleagues used data from the Promotion of Breastfeeding Intervention Trial, involving infants born at full term and weighing ≥2,500g, to examine the correlation between neonatal weight gain and head circumference gain in the first four weeks and IQ scores and behavior at age 6.5 years.

The researchers found that infants in the highest quartile of neonatal weight gain had 1.5-point higher IQ scores than those in the lowest quartile, in a fully adjusted model. For the teacher-reported, but not the parent-reported, Strengths and Difficulties Questionnaire, there was a weak negative (protective) association between neonatal weight gain and the total difficulties score. There were similar correlations noted for head circumference gain and IQ and behavior.

“Faster gains in weight or head circumference in the four weeks after birth may contribute to children’s IQ, but reverse causality (brain function affects neonatal growth) cannot be excluded,” the authors write.

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