Is the association between mothers' autistic traits and childhood autistic traits moderated by maternal pre-pregnancy body mass index?

This study looked at over 4,800 families to see if there's a connection between mothers' autism traits and their children's traits. They found that mothers with more autism traits tend to have children with more autism traits, from toddler years through early teens. The mother's weight before pregnancy didn't change this connection, but children of mothers who were underweight or overweight during pregnancy showed slightly higher autism traits.

This large cohort study examined whether maternal pre-pregnancy BMI moderates the relationship between mothers' and children's autistic traits across two populations (N=4,838). Researchers found consistent associations between maternal and child autistic traits from toddlerhood through early adolescence. Higher maternal autistic traits predicted higher child autistic traits across all age groups (β = 0.16-0.20). While higher maternal pre-pregnancy BMI was associated with increased child autistic traits in one cohort, BMI did not moderate the mother-child trait association in either cohort.

Interestingly, children of both underweight and overweight mothers showed higher autistic trait scores compared to children of mothers with healthy weight.

Findings support familial clustering of autistic traits and suggest maternal health factors may influence child neurodevelopment. Healthcare providers should consider family history of autistic traits and support optimal maternal health before and during pregnancy.

Study relies on questionnaire-based trait measures rather than clinical diagnoses. Maternal weight information was self-reported. The moderating effect of BMI was not replicated across both cohorts, limiting generalizability.

Previous studies showed that there is a positive association between mothers' and children's autistic traits. We also tested if this association is more pronounced in mothers with a higher pre-pregnancy body mass index (BMI). The study was embedded in two cohorts with information available for 4,659 participants from the Generation R and for 179 participants from the Cambridge Ultrasound Siblings and Parents Project (CUSP) cohort. In both cohorts, maternal autistic traits were assessed using the short form of the Autism Spectrum Quotient, and information about maternal height and weight before pregnancy was obtained by questionnaire.

Child autistic traits were assessed with the short form of Social Responsiveness Scale in Generation R (M = 13.5 years) and with the Quantitative Checklist for Autism in Toddlers (Q-CHAT) in the CUSP cohort (M = 1.6 years). Higher maternal autistic traits were associated with higher autistic traits in toddlerhood (CUSP cohort; β = 0.20, p < 0.01), in early childhood (Generation R; β = 0.19, p < 0.01), and in early adolescence (Generation R; β = 0.16, p < 0.01). Furthermore, a higher maternal pre-pregnancy BMI was associated with higher child autistic traits, but only in Generation R (β = 0.03, p < 0.01). There was no significant moderating effect of maternal pre-pregnancy BMI on the association between autistic traits of mothers and children, neither in Generation R nor in CUSP.

In addition, child autistic traits scores were significantly higher in mothers who were underweight and in mothers who were overweight compared to mothers with a healthy weight. We confirm the association between maternal and child autistic traits in toddlerhood, early childhood, and early adolescence. Potential interacting neurobiological processes remain to be confirmed.