Associations between maternal exposure to air pollution and birth outcomes: a retrospective cohort study in Taizhou, China

Abstract

Previous studies from Western country settings had shown correlation between maternal exposure to air pollution and pregnancy outcomes; however, the evidence is difficult to clearly interpret. We aimed to investigate the association of maternal exposure to air pollution expressed as particulate matter (PM_2.5, PM₁₀) and nitrogen dioxide (NO₂). The exposure was assessed for the 1st, 2nd, and 3rd trimester and related to the birth outcomes. During each trimester of gestation, the effect of PM_2.5, PM₁₀, and NO₂ exposure as well as the entire pregnancy on the preterm birth, low birth weight, and term babies' birth weight was explored. The dataset of 26,998 delivered live births between January 1, 2013 and May 31, 2016, were collected from the Taizhou Maternal and Child Care Service Center. Air monitoring data were collected from the Taizhou Municipal Environmental Monitoring Center for the same period. We used multi-variable logistic and linear regression analyses to investigate the correlation of air pollution to maternal and outcomes of birth. In models of adjusted single pollutant for second trimester, NO₂ concentration was positively correlated with term low birth weight and preterm birth [aRR for an interquartile range increase: 1.59 (1.44, 1.75); 1.27 (1.12, 1.44)]; likewise, a 1 μg/m³ increase in NO₂ was correlated with a reduction in birth weight 2.94 g (P < 0.001) in linear models. Each of PM_2.5 and PM₁₀ concentration was also associated with preterm birth [aRR for an interquartile range increase 1.30 (1.21, 1.38); 1.39 (1.27, 1.52)]. In co-pollutant models, the results were similar. Maternal exposure to air pollutant in Taizhou was associated with an increased risk of preterm birth and reduction in birth weight. We reported a potential link between maternal exposure to air pollution and negative outcomes of birth in Taizhou, China.