Do Ambient Air Pollutant Concentrations during Pregnancy Impact Birth Weight among Women Living in Monroe County, New York? The Rochester Accountability Study

Increased ambient air pollutant concentrations during pregnancy have been associated with reduced birth weight, but the etiologically-relevant time window during pregnancy is unclear. Therefore, we studied the association between gestational month ambient air pollutant concentrations and birth weight in Monroe County, NY (2005-2016). We also examined whether associations differed BEFORE implementation of several air quality policies (2005-2007), compared to DURING (2008-2013) and AFTER implementation (2014-2016). We used measurement of fine particles (PM2.5), black carbon (BC), ultrafine particles (UFP; <100nm), accumulation mode particles (AMP; 100-500nm), sulfur dioxide (SO2), and ozone (O3) in Rochester, NY (2005-2016) and birth certificate data for 76,500 singleton term births (37-42 gestational weeks at delivery) born to Monroe County residents. For each pollutant, we separately regressed birth weight against the mean concentration in each gestational month and the last 31 days of pregnancy (10 models). We then explored effect modification by PERIOD, season, infant gender, maternal employment, and pregnancy complications. Overall, there were no clear patterns of birth weight change associated with increased pollutant concentrations across gestational months. However, increased and decreased birth weights were associated with interquartile range increases in black carbon in the 1st gestational month (13.4g increase; 95% CI=3.4, 23.4), UFP in the 6th month (7.5g decrease; 95% CI=-14.5, -0.4), O3 in the 1st month (15.8g decrease; 95% CI=-31.5, -0.1) and O3 in the 6th month (17.2g increase; 95% CI=3.1, 31.4). There were also no patterns of effect modification by PERIOD, infant gender, maternal employment, pregnancy complications, or season. However, among Hispanic women only, increases in all pollutants, except O3, in multiple gestational months were associated with decreased birth weight. Further work is needed to understand these differences by ethnicity