Household Income, Maternal Allostatic Load During Pregnancy, and Offspring With Autism Spectrum Disorders.

ASD diagnosis was parent-reported at age 4 and not confirmed with standardized clinical criteria, though previous studies show high agreement between parent report and clinician diagnosis. The study measured allostatic load in the first or second trimester, which may be too early to capture the physiological stress relevant to fetal neurodevelopment, as optimal timing is proposed to be late in the second trimester. The measure of allostatic load did not include markers of sympathetic nervous system functioning (e.g., epinephrine, norepinephrine). The study did not adjust for paternal BAP or familial history of other psychiatric disorders, which could introduce residual confounding. Postnatal economic hardship was not assessed, so the study could not distinguish between the effects of prenatal versus postnatal income on child development. Children undiagnosed at age 4 may have received a diagnosis later, as the median age of diagnosis in the US is 49 months.

The authors declare no conflicts of interest. The study was funded by the Ministry of the Environment, Government of Japan.

Do not conclude that maternal physiological stress (allostatic load) is the mechanism linking low income to ASD risk. The study found that allostatic load did not significantly mediate this association, meaning the link between income and ASD diagnosis exists independently of the measured biomarkers of chronic stress.