Effects of air pollution on adverse birth outcomes and pregnancy complications in the U.S. state of Kansas (2000–2015)

Abstract

Neonatal mortality and morbidity are often caused by preterm birth and lower birth weight. Gestational diabetes mellitus (GDM) and gestational hypertension (GH) are the most prevalent maternal medical complications during pregnancy. However, evidence on effects of air pollution on adverse birth outcomes and pregnancy complications is mixed. Singleton live births conceived between January 1st, 2000, and December 31st, 2015, and reached at least 27 weeks of pregnancy in Kansas were included in the study. Trimester-specific and total pregnancy exposures to nitrogen dioxide (NO₂), particulate matter with an aerodynamic diameter less than 2.5 μm (PM_2.5), and ozone (O₃) were estimated using spatiotemporal ensemble models and assigned to maternal residential census tracts. Logistic regression, discrete-time survival, and linear models were applied to assess the associations. After adjustment for demographics and socio-economic status (SES) factors, we found increases in the second and third trimesters and total pregnancy O₃ exposures were significantly linked to preterm birth. Exposure to the second and third trimesters O₃ was significantly associated with lower birth weight, and exposure to NO₂ during the first trimester was linked to an increased risk of GDM. O₃ exposures in the first trimester were connected to an elevated risk of GH. We didn’t observe consistent associations between adverse pregnancy and birth outcomes with PM_2.5 exposure. Our findings indicate there is a positive link between increased O₃ exposure during pregnancy and a higher risk of preterm birth, GH, and decreased birth weight. Our work supports limiting population exposure to air pollution, which may lower the likelihood of adverse birth and pregnancy outcomes.