Maternal exposure to fine particulate matter in the air and risk for fetal congenital heart defects: A case-control study.

Prior research into the association between fine particulate matter (PM2.5) exposure and the risk for fetal congenital heart defect (CHD) has yielded inconclusive and conflicting results. More epidemiologic evidence from different regions is necessary. A case-control study was conducted with 360 CHD cases and 3600 healthy newborns. Both the cases and the controls were registered by the mothers in the Prenatal Health Care System during the first trimester and gave birth at hospitals in the Tongzhou District of Beijing between 2013 and 2018. Information on PM2.5 was obtained from satellite remote sensing monitoring data. We estimated average monthly PM2.5 exposure for participants from 3 months before the last menstrual period through 6 months of gestational period. A logistic regression model was used to estimate odd ratio (OR) (95 % confidence interval, CI) for PM2.5 exposure level and fetal risk for CHD. In our study, PM2.5 concentrations before pregnancy and in the first trimester were not associated with CHD risk. In the second trimester, 2nd high quartile PM2.5 group during the second month were associated with a lower CHD risk (adjusted OR(aOR)= 1.42, 95 % CI: 1.04-1.94) and highest quartile level group of PM2.5 exposure in the third month were associated with a reduced risk for fetal CHD (aOR=0.70, 95 % CI: 0.51-0.97). After Bonferroni's α correction, no comparisons were statistically significant. In conclusion, no associations were found between PM2.5 exposure level and fetal risk for CHD in our study.