Heat wave exposure during pregnancy and neurodevelopmental delay in young children: A birth cohort study

Gestation is a critical period for fetal brain development, and extreme heat exposure during this stage may have adverse impact on neurodevelopment in children. However, current evidence is scarce.

We examined the associations between maternal exposure to heat wave during pregnancy and neurodevelopmental delay in young children in a birth cohort study of 67,453 child-mother pairs from Foshan, China. Specifically, temperature data (spatial resolution: 0.0625° × 0.0625°) were assigned to study participants based on residential addresses. Then, heat wave events were defined by combining the intensity (temperature thresholds: ≥90th, 92.5th or 95th percentile) and duration (number of consecutive days: 2, 3 or 4 days). Neurodevelopmental status was assessed using a five-domain scale by trained medical professionals. Logistic regression was used to investigate the associations between gestational heat wave exposure and neurodevelopmental delay in children.

We found that exposure to heat wave during early and late pregnancy was associated with increased risks of neurodevelopmental delay in children. By contrast, the results for mid-pregnancy heat wave exposure were mixed. The observed associations remained stable in a group of sensitivity analyses.

Our study adds some suggestive evidence that prenatal exposure to heat wave may have detrimental impact on children's neurodevelopment. More investigations are needed to verify our findings.