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

Abstract

Introduction: 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.

Methods: 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.

Results: 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.

Conclusions: 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.