Abstract
OBJECTIVE: To collect maternal maternity information on preterm births in two tertiary hospitals in the urban area of Baota District, Yan'an City, from January 2018 to December 2020, to explore the long-term and short-term effects of air pollutants (PM(2.5), PM(10), SO(2), NO(2), CO and O(3)) and preterm births, and to explore changes in blood cell counts due to air pollutants. METHODS: Daily average mass concentration data of six air pollutants in the urban area of Yan'an City from January 1, 2017 to December 31, 2020 were collected from the monitoring station in Baota District, Yan'an City. Meteorological information was obtained from the Meteorological Bureau of Yan'an City, including temperature,relative humidity and wind speed for the time period. The mass concentration of air pollutants in each exposure window of pregnant women was assessed by the nearest monitoring station method, and conditional logistic regression was used to analyze the relationship between air pollutants and preterm births, as well as the lagged and cumulative effects of air pollutants. Multiple linear regression was used to explore the relationship between air pollutants and blood tests after stepwise linear regression was used to determine confounders for each blood test. RESULTS: The long-term effects of pollutants showed that PM(2.5), PM(10), SO(2), NO(2)and CO were risk factors for preterm birth. In the two-pollutant model, PM(2.5), PM(10), SO(2) and NO(2) mixed with other pollutants were associated with preterm birth. The lagged effect showed that PM(2.5), PM(10), SO(2), NO, and CO were associated with preterm birth; the cumulative effect showed that other air pollutants except O(3) were associated with preterm birth. The correlation study between air pollutants and blood indicators showed that air pollutants were correlated with leukocytes, monocytes, basophils, erythrocytes, hs-CRPand not with CRP. CONCLUSION: Exposure to air pollutants is a risk factor for preterm birth. Exposure to air pollutants was associated with changes in leukocytes, monocytes, basophils and erythrocytes and hs-CRP.