Acute effects of air pollutants on adverse birth outcomes in Changsha, China: A population data with time-series analysis from 2015 to 2017

Evidence for the acute effects of air pollutants on adverse birth outcomes is not yet conclusive. Furthermore, there are no investigations relating to the association between air pollutants and macrosomia. The aim of this study was to determine the relationship between air pollutants and low birth weight, preterm birth, and macrosomia in Changsha. Time-series analysis, using a generalized additive model was applied. Data about the adverse birth outcomes was collected from 78 midwifery institutions. Air pollution data including SO(2), NO(2), particulate matter <10 μm in diameter (PM(10)), particulate matter <2.5 μm in diameter (PM(2.5)), O(3), CO, and climate data were respectively collected from the Changsha Environmental Protection Agency and the Changsha Meteorological Bureau from January 2015 to December 2017. During the study period, there were 344,880 live births to be studied. In a single pollutant model, for every increase of 10 μg/m(3) in PM(10) and PM(2.5), low birth weight increased by 0.12% (95% confidence interval [CI]: 0.01–0.23%) at a lag 06 and 0.44% (95% CI: 0.35–0.53%) at a lag 3, respectively. Preterm birth increased most by 1.60% (95% CI: 1.41–1.80%) at a lag 2 for every increase of 10 μg/m(3) in SO(2). The highest increases in macrosomia associated with a 10 μg/m(3) increase in air pollutant were 3.53% (95% CI: 3.41–3.64%) for NO(2) at lag 0, 3.33% (95% CI: 3.05–3.60%) for SO(2) at lag03. Multi-pollutant models showed that only PM(10) increased the low birth weight and preterm birth risk effect by 3.91% (95% CI: 3.67–4.12%) and 0.25% (95% CI: 0.14–0.37%). NO(2) increased macrosomia risk by 4.14% (95% CI: 3.97–4.31%) with a 10 μg/m(3) increase. There was no association observed between the air pollutants O(3) and CO and adverse birth outcomes. Pregnant women should also take steps to limit their exposure to high levels of air pollutants during the final weeks of pregnancy.