On the Spectrum

A Prospective Study of Fetal Head Growth in Children, Autistic Traits and Autism Spectrum Disorder
Another potential limitation concerns the differential measurement of autistic traits across
the two cohorts: while the two measures of autistic traits are aimed at measuring similar
constructs, the age of administration (6 vs. 20) and the reporter (mother vs. self) differ, which
potentially complicates direct comparison. However, autistic traits have been found to be
relatively stable across development (Robinson, Munir, Munafo, Hughes, McCormick et al.
2011; Whitehouse et al. 2011) and despite the difference in age of outcome, associations
with prenatal HC growth were similar across cohorts. Finally, both study samples were more
likely to include mothers from more privileged families, with several characteristics that are
generally beneficial for fetal growth. This could have affected our findings.
In conclusion, we present findings on prenatal HC growth trajectories in children with
autistic symptoms from two independent, prospective, longitudinal prenatal cohort studies.
We found that subjects with autistic symptoms slower HC growth during prenatal life, but
found no differences in prenatal head growth for children with ASD. Our results indicate that
prenatal growth could be important for the development of autistic traits. Future research
should clarify the mechanisms involved.
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