Ozone and Other Air Pollutants and the Risk of Congenital Heart Defects

The objective of this study was to evaluate whether high levels of maternal exposure to O 3 , SO 2 , NO 2 , CO are related to increased risk of congenital heart defects (CHDs) in Wuhan, China. The study included mothers living in the central districts of Wuhan during pregnancy over the two-year period from June 10, 2011 to June 9, 2013. For each study participant, we assigned 1-month averages of O 3 , SO 2 , NO 2 and CO exposure based on measurements obtained from the nearest exposure monitor to the living residence of mothers during their early pregnancy period. In one-pollutant model, we observed an increased risk of CHDs, ventricular septal defect (VSD), and tetralogy of fallot (TF) with increasing O 3 exposure. In two-pollutant model, associations with all CHDs, VSD, and TF for O 3 were generally consistent compared to the models that included only O 3 , with the strongest aORs observed for exposures during the third month of pregnancy. We also observed a positive association between CO exposures during the third month of pregnancy and VSD in two pollution model.Our results contribute to the small body of evidence regarding air pollution exposure and CHDs, but confirmation of these associations will be needed in future studies.