Impact of air pollution exposure during various periods of pregnancy on term birth weight: a large-sample, retrospective population-based cohort study

Li Shang,Leqian Guo,Longtao Leng,Liren Yang,Ruiqi Wang,Mei Chun Chung,Cuifang Qi,Wenfang Yang,Liyan Huang,Guilan Xie

doi:10.1007/s11356-020-10705-3

Abstract

Previous studies have suggested that maternal exposure to air pollution might affect term birth weight. However, the conclusions are controversial. Birth data of all term newborns born in Xi’an city of Shaanxi, China, from 2015 to 2018 and whose mother lived in Xi’an during pregnancy were selected form the Birth Registry Database. And the daily air quality data of Xi’an city was collected from Chinese Air Quality Online Monitoring and Analysis Platform. Generalized additive models (GAM) and 2-level binary logistic regression models were used to estimate the effects of air pollution exposure on term birth weight, the risk term low birth weight (TLBW), and macrosomia. Finally, 321521 term newborns were selected, including 4369(1.36%) TLBW infants and 24,960 (7.76%) macrosomia. The average pollution levels of PM2.5, PM10, and NO2 in Xi’an city from 2015 to 2018 were higher than national limits. During the whole pregnancy, maternal exposure to PM2.5, PM10, SO2, and CO all significantly reduced the term birth weight and increased the risk of TLBW. However, NO2 and O3 exposure have significantly increased the term birth weight, and O3 even increased the risk of macrosomia significantly. Those effects were also observed in the first and second trimesters of pregnancy. But during the third trimester, high level of air quality index (AQI) and maternal exposure to PM2.5, PM10, SO2, NO2, and CO increased the term birth weight and the risk of macrosomia, while O3 exposure was contrary to this effect. The findings suggested that prenatal exposure to air pollution might cause adverse impacts on term birth weight, and the effects varied with trimesters and pollutants, which provides further pieces of evidence for the adverse effects of air pollution exposure in heavy polluted-area on term birth weight.

Highlights

With the rapid development of global industrialization and urbanization, the problem of ambient air pollution has been getting increasingly prominent, which is the largest health environmental risk affecting all regions, socioeconomic groups, and age groups (Brauer et al 2016)
Some epidemiological studies indicated that maternal exposure to air pollution had adverse effects on infant health, such as adverse birth outcome and respiratory and neurodevelopmental effects (Backes et al 2013; Forns et al 2018; Korten et al 2017; Pedersen et al 2017; Shang et al 2019; Yorifuji et al 2015)
Per 10 μg/m3 increase of PM2.5, PM10, SO2, and per 0.1 mg/m3 increase of CO exposure all significantly reduced the term birth weight of newborns (β(95%confidence intervals (CIs)) values were − 2.739 (− 3.693, − 1.785), − 2.458 (− 3.116, − 1.800), − 3.982 (− 5.511, − 2.453) and − 1.511 (− 1.970, − 1.053), respectively) and increased the risk of term low birth weight (TLBW) (OR (95%CI) values were 1.025 (1.005–1.045), 1.035 (1.020– 1.049), 1.034 (1.004–1.065), and 1.013 (1.004–1.023), respectively)

Summary

Introduction

With the rapid development of global industrialization and urbanization, the problem of ambient air pollution has been getting increasingly prominent, which is the largest health environmental risk affecting all regions, socioeconomic groups, and age groups (Brauer et al 2016). Some studies have suggested that air pollutants might increase the risk of cardiovascular and respiratory diseases through inducing some abnormal reactions, such as oxidative stress and DNA methylation (Chen et al 2020a; Chu et al 2015; Kaufman et al 2016). Some epidemiological studies indicated that maternal exposure to air pollution had adverse effects on infant health, such as adverse birth outcome and respiratory and neurodevelopmental effects (Backes et al 2013; Forns et al 2018; Korten et al 2017; Pedersen et al 2017; Shang et al 2019; Yorifuji et al 2015). Abnormal birth weight (including low birth weight (LBW) and macrosomia) is generally associated with several long-term chronic diseases in adults, including cardiovascular disease, type 2 diabetes, and certain cancers (Moraitis et al 2014; Zhang et al 2014)

Methods

Discussion

Conclusion