Background: Preeclampsia is a major pregnancy complication leading to substantial maternal and perinatal morbidity, mortality, and preterm birth. Increasing evidence suggests air pollution adversely affects pregnancy outcomes. Yet, few studies have examined how local trafficgenerated emissions affect preeclampsia in addition to preterm birth.
Objectives: Examine effects of residential exposure to local traffic-generated air pollution on preeclampsia and preterm delivery.
Methods: We identified 81,186 singleton birth records from four hospitals (1997-2006) in Los Angeles and Orange Counties, California. We used a line-source dispersion model (CALINE4) to estimate individual exposure to local traffic-generated NOx and PM2.5 across the entire pregnancy. We used logistic regression to estimate effects of air pollution exposures on preeclampsia, preterm delivery (PTD, gestational age <37 weeks), moderate preterm delivery (MPTD, gestational age <35 weeks), and very preterm delivery (VPTD, gestational age <30 weeks).
Results: We observed elevated risks for preeclampsia and preterm birth from maternal exposure to local traffic-generated NOx and PM2.5. The risk of preeclampsia increased 33% (odds ratio (OR) =1.33, 95% confidence interval (CI): 1.18?1.49) and 42% (OR=1.42, 95% CI: 1.26?1.59) for the highest NOx and PM2.5 exposure quartiles, respectively. The risk of VPTD increased 128% (OR=2.28, 95% CI: 2.15?2.42) and 81% (OR=1.81, 95% CI: 1.71?1.92) for women in the highest NOx and PM2.5 exposure quartiles, respectively.
Conclusion: Exposure to local traffic-generated air pollution during pregnancy increases the risk of preeclampsia and preterm birth in Southern Californian women. These results provide
further evidence that air pollution is associated with adverse reproductive outcomes.