Maternal age at childbirth and social development in infancy

Abstract Difficulties in social communication are not necessarily observed only in individuals with autism spectrum disorders (ASD), and there are many subclinical cases in the general populations. Although advanced parental age at childbirth has often been considered a possible risk factor of ASD, it might contribute to poor social functioning in children, rather than to ASD itself. This study examined whether advanced maternal age at childbirth and obstetric factors were associated with atypical social development in infancy. At free health check-ups for children aged 18 months conducted in Munakata city, Japan, 1460 children (729 males) were assessed using the Japanese version of the Modified Checklist for Autism in Toddlers (M-CHAT). Adjusted odds ratio showed that children of mothers aged ≥35 years at childbirth were 2.22 (95% confidence intervals, 1.39–3.55) times more likely to fail on the M-CHAT (failing three or more items) compared with the reference group (aged ≤29). Although most mothers will have toddlers that fall in the typical range on this measure of social development, clinicians should pay more attention to early social development of children, especially for lateborn babies, and should be more sensitive to their potential needs so as to provide appropriate advice and support for their caregivers.