Ambient exposure to fine particulate matter with oxidative potential affects oxidative stress biomarkers in pregnancy.

Prenatal exposures to ambient particulate matter (PM2.5) from traffic may generate oxidative stress and thus contribute to adverse birth outcomes. We investigated whether PM2.5 constituents from brake and tire wear affect levels of oxidative stress biomarkers (malondialdehyde [MDA], 8-hydroxy-2'-deoxyguanosine [8-OHdG]) using urine samples collected up to 3 times during pregnancy in 156 women recruited from antenatal clinics at the University of California Los Angeles. Land use regression models with co-kriging were employed to estimate average residential outdoor concentrations of black carbon (BC), PM2.5 mass, PM2.5 metal components, and 3 PM2.5 oxidative potential metrics during the 4 weeks prior to urine sample collection. The 8-OHdG concentrations in mid-pregnancy increased by 24.8% (95% confidence interval [CI], 9.0-42.8) and 14.3% (95% CI, 0.4%-30.0%) per interquartile range (IQR) increase in PM2.5 mass and BC, respectively. The brake wear marker (barium) and the oxidative potential metrics were associated with increased MDA concentration in the first sample collected (10-17 gestational week), but 95% CIs included the null. Traffic-related air pollution contributed in early to mid-pregnancy to oxidative stress generation previously linked to adverse birth outcomes. This article is part of a Special Collection on Environmental Epidemiology.