Association of Fine Particulate Matter and Its Components with Macrosomia: A Nationwide Birth Cohort Study of 336 Chinese Cities

Prenatal exposure to PM2.5, especially to itsfuel combustion-related components, was associated with increasedmacrosomia risk. Toexamine the associations between macrosomia risk and exposureto fine particulate matter (PM2.5) and its chemical componentsduring pregnancy, we collected birth records between 2010 and 2015in mainland China from the National Free Preconception Health ExaminationProject and used satellite-based models to estimate concentrationsof PM2.5 mass and five main components, namely, black carbon(BC), organic carbon (OC), nitrate (NO3 (-)), sulfate (SO4 (2-)), and ammonium (NH4 (+)). Associations between macrosomia risk and prenatalexposure to PM2.5 were examined by logistic regressionanalysis, and the sensitive subgroups were explored by stratifiedanalyses. Of the 3,248,263 singleton newborns from 336 cities, 165,119(5.1%) had macrosomia. Each interquartile range increase in concentrationof PM2.5 during the entire pregnancy was associated withincreased risk of macrosomia (odds ratio (OR) = 1.18; 95% confidenceinterval (CI), 1.17-1.20). Among specific components, the largesteffect estimates were found on NO3 (-) (OR= 1.36; 95% CI, 1.35-1.38) followed by OC (OR = 1.23; 95% CI,1.22-1.24), NH4 (+) (OR = 1.22; 95% CI,1.21-1.23), and BC (OR = 1.21; 95% CI, 1.20-1.22). Wealso that found boys, women with a normal or lower prepregnancy bodymass index, and women with irregular or no folic acid supplementationexperienced higher risk of macrosomia associated with PM2.5 exposure.