The Association Between Traffic Exposure And Adverse Pregnancy Outcomes In Chongqing

Background: With the development of China's economy and the acceleration of urbanization,air pollution has become one of the most important environmental issues.The impact of air pollution on human health,especially on pregnant women and fetuses,has received considerable attention.Studies have shown that exposure to higher concentration of air pollutants during pregnancy can lead to adverse pregnancy outcomes.Chongqing is a famous "Fog City".In recent years,although the "close,stop,merge,transfer,and relocation" measures have been adopted for industrial enterprises that seriously affect the air quality of the city,the air quality has improved.However,with the rapid increase in the number of motor vehicles,the exponential load of atmospheric inhalable particles increased,and the contribution of automobile exhaust to the concentration of suspended particulate matter increased most significantly.Chongqing is also known as "mountain city".Its special geographical environment makes it difficult for air pollutants to diffuse.At present,Chongqing still lacks research on the relationship betweentraffic-related pollution and pregnancy outcomes,therefore,this study is worth conducting.Methods: This is a prospective cohort study in Chongqing.A questionnaire survey was conducted to collect information of 703 pregnant women who received the first prenatal examination in the First Affiliated Hospital of Chongqing Medical University from September 2015 to August2016.The pregnant women were divided into two groups according to the distance between the residence and the main road.A total of 618 pregnant women lived ?250 meters from the main road,and a total of 85 pregnant women lived <250 meters,The pregnancy outcomes of the two groups were followed up.A multi-factor analysis method was used,the logistic regression was used to analyze the relationship between residential proximity to main road and premature birth,gestational diabetes mellitus,premature rupture of membranes,low birth weight and macrosomia,respectively.Multiple linear regression was used to explore the associations between residential proximity to main road and neonatal weight and body length.Results: After adjusting for the possible confounding factors(ethnicity,household income,smoking and education level),taking the pregnant woman's residence at a distance of ?250 meters from the main road as a control,the distance <250 meters is not a risk factor for preterm birth(OR=0.669,95%CI=0.153-2.972,P=0.593),gestational diabetesmellitus(OR=0.784,95%CI=0.454-1.353,P=0.382),premature rupture of membranes(OR=1.120,95%CI=0.672-1.867,P=0.664),low birth weight(OR=1.626,95%CI=0.455-5.809,P=0.454)and macrosomia(OR=1.932,95%CI=0.763-4.890,P=0.165),nor did it affect the weight(OR=0.037,95%CI=-49.746-146.518,P=0.333)and length(OR=0.009,95%CI=-0.350-0.445,P=0.813)of the newborn.Conclusion: The results of this study suggest that the distance between the address of pregnant women and the main road <250 meters is not a risk factor adverse pregnancy outcomes in Chongqing.