The impact of PM2.5 component exposure during early pregnancy on congenital heart disease: evidence from Guangdong, China

Limited is known about how the components of particulate matter with aerodynamic diameter < 2.5 μm (PM 2.5 ) are related to congenital heart disease (CHD). We aimed to demonstrate the relationship between exposure to PM 2.5 components during early pregnancy and the risk of CHD. This study included 2,601,300 live births and stillbirths in Guangdong, China from 2014 to 2017. Satellite remote sensing data of PM 2.5 components were collected, including organic matter (OM), sulfate ( SO₄²⁻ ), nitrate ( NO₃⁻ ), ammonium ( NH₄⁺ ), and black carbon (BC). Unconditional logistic regression models were constructed to estimate the relationship of each PM 2.5 component to CHD. The quantile g-computation method was used to evaluate the contribution weight of each PM 2.5 component in relation to CHD in the exposure mixture. The estimated effect size of each PM 2.5 component peaked in the first week of pregnancy. Among them, SO₄²⁻ exhibited the strongest estimated effect (OR: 2.23, 95% CI 2.19–2.27), followed by BC (OR: 1.95, 95% CI 1.91–1.98). The joint exposure analysis revealed that the estimated weights of SO₄²⁻ and BC were 86.78% and 13.22%, respectively. These findings suggest that exposure to PM 2.5 components during early pregnancy increases the risk of CHD in the offspring, and SO₄²⁻ may be the primary PM 2.5 component responsible for this elevated risk.