Exposures to Air Pollutants during Pregnancy and Preterm Delivery

• Published in: Environmental health perspectives Vol. 114; no. 6; pp. 905 - 910
• Main Authors: Leem, Jong-Han, Kaplan, Brian M., Shim, Youn K., Pohl, Hana R., Gotway, Carol A., Bullard, Stevan M., Rogers, J. Felix, Smith, Melissa M., Tylenda, Carolyn A.
• Format: Journal Article
• Language: English
• Published: United States National Institute of Environmental Health Sciences. National Institutes of Health. Department of Health, Education and Welfare 01-06-2006; National Institute of Environmental Health Sciences
• Subjects: Air pollutants; Air Pollutants - toxicity; Air pollution; Children's Health; Environmental Exposure; Environmental health; Female; First trimester of pregnancy; Gestational age; Humans; Infants (Premature); Infections; Korea; Kriging; Maternal Exposure; Pregnancy; Pregnancy outcome; Pregnant women; Premature Birth; Third trimester of pregnancy; Korea; South Korea; Korea, Rep
• ISSN: 0091-6765; 1552-9924
• DOI: 10.1289/ehp.8733

The association between preterm delivery (PTD) and exposure to air pollutants has recently become a major concern. We investigated this relationship in Incheon, Republic of Korea, using spatial and temporal modeling to better infer individual exposures. The birth cohort consisted of 52,113 singleton births in 2001-2002, and data included residential address, gestational age, sex, birth date and order, and parental age and education. We used a geographic information system and kriging methods to construct spatial and temporal exposure models. Associations between exposure and PTD were evaluated using univariate and multivariate log-binomial regressions. Given the gestational age, birth date, and the mother's residential address, we estimated each mother's potential exposure to air pollutants during critical periods of the pregnancy. The adjusted risk ratios for PTD in the highest quartiles of the first trimester exposure were 1.26 [95% confidence interval (CI), 1.11-1.44] for carbon monoxide, 1.27 (95% CI, 1.04-1.56) for particulate matter with aerodynamic diameter $\leq 10 \mu m$, 1.24 (95% CI, 1.09-1.41) for nitrogen dioxide, and 1.21 (95% CI, 1.04-1.42) for sulfur dioxide. The relationships between PTD and exposures to CO, NO2, and SO2 were dose dependent (p < 0.001, p < 0.02, p < 0.02, respectively). In addition, the results of our study indicated a significant association between air pollution and PTD during the third trimester of pregnancy. In conclusion, our study showed that relatively low concentrations of air pollution under current air quality standards during pregnancy may contribute to an increased risk of PTD. A biologic mechanism through increased prostaglandin levels that are triggered by inflammatory mediators during exposure periods is discussed.