What Do They Say About Big Babies?

Birth weight of babies linked to brain size as they grow up

/ Author:  / Reviewed by: Robert Carlson, M.D

(RxWiki News) So what do they say about big babies? Well, aside from bigger feet, bigger arms, bigger toes and a bigger nose, it appears they have bigger brains too.

A recent study used brain scans to look inside hundreds of kids' heads. Researchers found that a child's birth weight is linked to their brain size. Therefore, aspects of a person's development are already influenced by their brains at birth.

These findings also mean that even small differences in birth weight are important to consider in research into mental health issues, such as personality disorders and attention deficit-hyperactivity disorder (ADHD).

"Attend all prenatal appointments."

The study, led by Kristine B. Walhovd in the Department of Psychology at the University of Oslo in Norway, aimed to find out whether there was a link between a baby's birth weight and their brain development.

The brains of 628 healthy children, teens and young adults from throughout the US were studied with magnetic resonance imaging (MRI) scans. The researchers were specifically looking at the participants' total brain volume and one section's volume as well as the brain's surface area and "cortical thickness."

The cortical thickness refers to the thickness of the different layers combined in the brain's cerebral cortex.

In their analysis, the researchers made adjustments to account for differences among the children in terms of their age, gender, household income and genetic ancestry (hereditary history). They found that the surface area in several regions of the brain and overall brain size were linked to a child's birth weight.

Across all ranges of birth weights, the larger the child's weight at birth, the larger these areas in their brains were, including the overall volume of the brain.

"The findings show that aspects of later child and adolescent brain development are influenced at birth," the authors wrote.

The study was published November 19 in the Proceedings of the National Academy of Sciences. The research was funded by the PING Study from the National Institutes of Health, the National Institute on Drug Abuse and the Eunice Kennedy Shriver National Institute of Child Health and Human Development. One author reported founding CorTechs Labs, as well as serving on their scientific advisory board.

Reviewed by: 
Review Date: 
November 20, 2012
Last Updated:
April 2, 2013