Association of prenatal exposure to ambient air pollution with adverse birth outcomes and effect modification by socioeconomic factors

BackgroundMaternal exposure to air pollution has been associated with birth outcomes; however, few studies examined biologically critical exposure windows shorter than trimesters or potential effect modifiers.ObjectivesTo examine associations of prenatal fine particulate matter (PM2.5), by trimester and in biologically critical windows, with birth outcomes and assess potential effect modifiers.MethodsThis study used two pregnancy cohorts (CANDLE and TIDES; N = 2099) in the ECHO PATHWAYS Consortium. PM2.5 was estimated at the maternal residence using a fine-scale spatiotemporal model, averaged over pregnancy, trimesters, and critical windows (0-2 weeks, 10-12 weeks, and last month of pregnancy). Outcomes were preterm birth (PTB,