The effects of exposure to ambient PM 2.5 during pregnancy on septal defects in offspring: A retrospective population-based case-control study

Recent epidemiological studies conducted over the past ten years have increasingly investigated the association between ambient air pollution exposure and the risk of congenital heart defects, yet the findings have shown considerable inconsistency across different research populations and methodological approaches. This study sought to examine the association between maternal exposure to fine particulate matter (PM2.5) during the critical first eight weeks of gestation and the risk of septal defects in offspring. A population-based case-control study in Beijing, China (2008-2012) was conducted to assess the association between maternal exposure to PM2.5 during the first eight weeks of pregnancy and the risk of septal defects in offspring. Multi-variable logistic regression regression models were used to estimated adjusted odds ratio (aOR) and corresponding 95% confidence intervals (CIs) for exposure-risk association, and the exposure-response association was investigated using restricted cubic spline analysis. Maternal exposure to PM2.5 were positively associated with the risk of overall septal defects in the 10th-50th percentile (aOR = 2.415; 95%CI: 1.424 to 4.359), 51th-90th percentile (aOR = 2.539; 95%CI: 1.472 to 4.643), and > 90th percentile (aOR = 2.991; 95%CI: 1.601 to 5.832) groups during the fourth week, and in the 10th-50th percentile (aOR = 1.432; 95%CI: 0.899 to 2.362), 51th-90th percentile (aOR = 1.874; 95%CI: 1.162 to 3.128), and > 90th percentile (aOR = 2.468; 95%CI: 1.398 to 4.453) groups during the fifth week, all compared with the < 10th percentile group. Non-isolated atrial septal defect demonstrated the strongest association with PM2.5 exposure during these weeks (aOR range: 1.882 to 4.382). Individual characteristics showed no meaningful effect modification. Furthermore, PM2.5 exposure exhibited a linear dose-response association with overall septal defects. This study identified a significant positive association between maternal exposure to ambient PM2.5 during the first eight gestational weeks and fetal septal defects.