Exposure to Fine Particulate Matter During Pregnancy Is Associated With Hippocampal Development in Offspring.

Background: As the global climate crisis persists, it becomes increasingly important to understand how exposure to environmental toxins can affect the developing brain. Although researchers are beginning to document links between prenatal exposure to air pollution and brain structure, it is not clear when these associations emerge.

Methods: We leveraged data from the GUSTO (Growing Up Toward Healthy Outcomes in Singapore) longitudinal birth cohort study to examine prenatal exposure to air pollution and brain development during childhood. Spatiotemporally interpolated prenatal exposure to particulate matter <2.5 μm was averaged across each prenatal week. Structural magnetic resonance imaging data were obtained when children were ages 4.5, 6.0, 7.5, and 10.5 years ( = 325, 47.7% female) and segmented with FreeSurfer 7.1. A subset of parents completed the Child Behavior Checklist at the final assessment ( = 195, 46.7% female). We used latent growth modeling to estimate a slope of hippocampal volume growth in each hemisphere from ages 4.5 to 10.5 years, adjusted for intracranial volume.

Results: Distributed lag models indicated that late gestational exposure (during weeks 36-40) was associated with slower hippocampal growth in both hemispheres. Importantly, we also found that faster hippocampal volume growth in the right hemisphere was associated with more externalizing and attention problems at 10.5 years.

Conclusions: Future research should examine mechanisms that may underlie or contribute to these associations. These findings underscore the importance of efforts to reduce pollution, particularly for pregnant people and their children.