The Relationship Between Air Pollution And Adverse Birth Outcomes In Zhejiang Province,China

Air pollution is closely correlated with human health,and as a special susceptible population,pregnant women and newborns have received much attention.Premature birth and low birth weight have constituted one of the major causes of neonatal morbidity and mortality,and to a certain extent would bring about children's short-term or long-term health defects.Many studies have confirmed a certain association between pregnant women's exposure to ambient air pollution and PTB and LBW,but most previous studies considered only one kind of air pollutants,such as PM_2.5,or simply the exposure during entire pregnancy.Based on the medical data of 6274 newborns collected by the Women's Insurance of Zhejiang Province from2013 to2017 and the monitoring data of different air pollutants at 47 air monitoring stations,the levels of air pollution and the differences in spatial-temporal distribution in Zhejiang province during 2013-2017 were evaluated and the potential correlation between air pollution and neonatal premature birth and low birth weight were investigated using Poisson regressions and logistic regressions.The quantified risks of adverse birth outcomes associated with gestational exposure to air pollution and the susceptibilities of different periods of pregnancy to air pollution were assessed.Dose-response curves were utilized to estimate the critical concentration of various air pollutants for the risk of adverse impacts on pregnant women and newborns.This study could not only function as a methodological reference for the environmental epidemiology in China,but also provide a scientific evidence for the relevant government departments to formulate measures to control air pollution and reduce the incidence of adverse neonatal birth outcomes,which is of great significance for protecting public health.The results revealed that in principle,the levels of air pollution in Zhejiang Province dropped from 2013 to 2017.Averagely,the air pollution levels in winter were higher than the other three seasons,and among cities in Zhejiang province,Hangzhou,Shaoxing,Jinhua and Huzhou had more serious air pollution.Particular attention should be paid to the pollution levels of PM_2.5and O₃.Considering the entire concentration range of air pollutants,most mothers were exposed to relatively medium or high levels of PM_2.5,PM₁₀,NO₂,O₃and low levels of SO₂and CO.The average birth weight of 6,274 newborns was 3274.4 g,of which 5.93%were premature and 4.02%were low birth weight.Among multiple covariates,maternal BMI,parity,and gestational hypertension were risk factors for PTB in this research.After adjusting all covariates,in terms of the increasing of the concentrations of PM_2.5,SO₂,NO₂,CO,and O₃in the atmosphere by 1?g/m³,the RRs for PTB are 1.16?95%CI:1.00,1.35?,1.90?95%CI:1.13,3.20?,1.29?95%CI:1.00,1.01?,1.01?95%CI:1.00,1.01?And 1.08?95%CI:1.03,1.12?,respectively and the RRs for LBW are 2.26?95%CI:1.17,4.38?,1.26?95%CI:1.01,1.58?,1.01?95%CI:1.00?,1.01)and 1.05?95%CI:1.01,1.11?,respectively.In the three gestation periods,the risk of PTB is mainly related to the exposure to PM_2.5,NO₂and O₃in the first trimester and the exposure to SO₂during the third trimester.The risk of LBW is mainly related to the exposure to O₃during the first trimester,the exposure to NO₂during the second trimester and the exposure to PM_2.5,NO₂and CO during the third trimester,respectively.In this study,the contributions of PM_2.5,SO₂,NO₂,CO,and O₃to PTB are 14.9%,36.2%,19.4%,19.6%,and 9.9%and the contributions of these pollutants to LBW are 3.2%,49.8%,19.0%,21.2%and 6.8%,respectively.Mothers with high blood pressure during pregnancy had a higher risk of premature delivery and low birth weight of the newborns than normal mothers.The risk of CO exposure for LBW was only reflected in mothers with pregnancy-induced hypertension.Statistically,the increasing of the PM_2.5,SO₂,NO₂,CO,and O₃exposure concentrations during pregnancy by 1?g/m3would imply the decreasing of the birth weight of the newborns by 11.2g,14.0g,17.9g,0.27g,and 23.3g,respectively.The critical concentrations of PM_2.5,SO₂,NO₂,CO and O₃for PTB risk are:58?g/m³,13?g/m³,47?g/m³,850?g/m³,55?g/m³,and the critical concentrations for LBW risk are 47?g/m³,13?g/m³,45?g/m³,1150?g/m³and 68?g/m³.