The Association Between Maternal PM_2.5 Exposure And Preterm Birth In Wuhan

Objective:Most of studies regarding air pollution and preterm birth?PTB?in highly polluted areas have assessed exposure level based on fixed-site monitoring.However,exposure assessment methods relying on monitors have the potential to cause exposure misclassification due to a lack of spatial variation.In this study,we utilized a land use regression?LUR?model to assess individual exposure in Wuhan city,China,which has high levels of air pollution.Methods:Information on 2101 singleton births,which were?20 weeks of gestation and born between November 1,2013 and May 31,2014;between January 1,2015 and August 31,2015,was obtained from the Obstetrics Department in one 3A hospital in Wuhan.Air quality index?AQI?data were accessed from the Wuhan Environmental Protection Bureau website.Individual exposure during pregnancy was assessed by LUR models and Kriging interpolation.Logistic regression analyses were conducted to determine the association between women exposure to PM_2.5and the risk of different subtypes of PTB in different exposure windows.Also,we explore the exposure-response relationship between PM_2.5exposure and different subtypes of PTB.Results:?1?During the study period,the average individual exposure concentration of PM_2.5during the entire pregnancy was 84.54?g/m³.The average exposure concentration was lowest in the first trimester,and the average value was 69.12?g/m³.In the second trimester and the third trimester,PM_2.5exposure concentration were92.28?g/m³and 92.22?g/m³.?2?A 10?g/m³increase of PM_2.5exposure in the first trimester?OR:1.169;95%CI:1.077,1.262?,the second trimester?OR:1.056;95%CI:1.015,1.097?,the third trimester?OR:1.052;95%CI:1.002,1.101?,and the entire pregnancy?OR:1.263;95%CI:1.158,1.368?were significantly associated with an increased risk of PTB.The first trimester was the most susceptive exposure window.For the PTB subgroup,the hazard of PM_2.5exposure during pregnancy was stronger for very preterm births?VPTB??OR:1.496;95%CI:1.222,1.778?than moderate preterm births?MPTB??OR:1.23;95%CI:1.118,1.344?.?3?Exposure-response relationship of these two types of preterm birth?VPTB and MPTB?may be different at a relatively high exposure level.Compared with MPTB,VPTB is more sensitive to the increased exposure level of PM_2.5.?4?Pregnancy women who had less than 9 years of education or who conceived during the cold season tended to be more sensitive to the PM_2.5exposure during pregnancy.Conclusions:maternal PM_2.5exposure increased the risk of preterm birth,and the effect of PM_2.5exposure during pregnancy on VPTB was larger than on MPTB.The first trimester was the most susceptive exposure window.