Autism and head circumference in the first year of life

It has been reported that children with autism and pervasive developmental disorder have a significantly smaller head circumference at birth and that their head circumference then increases disproportionately rapidly in the first year of life. We attempted to replicate these findings using 15 narrowly defined autistic children from the National Collaborative Perinatal Project and approximately 40,000 nonautistic control subjects. The autistic group had a slightly but not significantly larger head circumference at birth. At 4 months, the head circumference in the autistic group was not significantly larger than that of control subjects, but body weight and length were significantly larger in the autistic group. We believe this is the first report of significant general body growth in autistic children in infancy; the larger head circumference may be part of this excessive general growth.