Ambient wintertime particulate air pollution and hypertensive disorders of pregnancy in Monroe County, New York.

Background: Previous studies have reported associations between ambient fine particle (PM) concentrations and hypertensive disorders of pregnancy (HDP). However, none have examined whether ultrafine particles (UFP; < 100 nm), accumulation mode particles (AMP; 100-500 nm), markers of traffic pollution (black carbon; BC), or wood burning (Delta-C; (30% of ambient wintertime PM in Monroe County, NY is from wood burning)) are associated with an increased odds of HDP. We estimated the odds of HDP associated with increased concentrations of PM, UFP, AMP, BC, and Delta-C in each gestational month during winter months.

Methods: Electronic medical records and birth certificate data were linked with land-use regression models in Monroe County, New York in 2009-2013 to predict monthly pollutant concentrations during winter (November-April) based on maternal residential address for 16,637 births. Using multivariable logistic regression, we estimated the odds of HDP associated with each interquartile range (IQR) increase in PM, UFP, AMP, BC, and Delta-C concentrations during each gestational month, adjusting for maternal characteristics, birth hospital, temperature, and relative humidity.

Results: Each 0.52 µg/m increase in Delta-C concentration during the 7th gestational month was associated with an increased odds of HDP (odds ratio (OR) = 1.21; 95% confidence interval (CI) = 1.01, 1.45), with a similar sized estimate in month 8 (OR = 1.18; 95%CI = 0.98, 1.43). Non-statistically significant increased odds of HDP associated with IQR increases in BC concentrations during months 3 (OR = 1.12; 95%CI = 0.98, 1.28) and 7 (OR = 1.12; 95%CI = 0.96, 1.29) were observed. Increased odds of HDP were not observed for PM, UFP, or AMP.

Conclusions: Our findings suggest that maternal exposure to wood smoke in Monroe County during winter is associated with an increased odds of HDP during late gestation. Additional studies are needed to evaluate the effect of wood smoke on HDP and to explore effects on other pregnancy outcomes.