The Effects of Prenatal Exposure to PM2.5 on Fetal Growth: Evidence from a Birth Cohort Study in China

Abstract

Objectives: We aimed to investigate the effects of PM2.5 exposure on fetal growth, and further clarify the susceptible exposure window based on a birth cohort in China.Methods: Pregnant women who had their prenatal care in the first trimester were recruited in the obstetrical clinics, and were followed up till their delivery time. Their personal information was collected by questionnaire, and their clinical information was obtained through their medical records. Each participant’s individual exposure to PM2.5 during the pregnancy was assessed using an spatio-temporal modelling that integrated a land-use-regression model and individual activity pattern.Results: A total of 2,845 pregnant women were recruited in this study, with an average age of 31 years. The average PM2.5 exposure during the entire pregnancy was 31.14μg/m3. The results of multiple linear regression analyses show that after adjustment for potential confounding factors each 10μg/m3 increase in PM2.5 exposure during the first trimester was associated with 1.55cm decrease in crown heel length in the first trimester, and 0.17cm less in birth length. Each 10μg/m3 increase in PM2.5 exposure during the second trimester was linked to decreases in head circumference, abdomen circumference, biparietal diameter and femur length by 2.38cm, 2.05cm,0.90cm and 1.12cm, respectively. However, the PM2.5 exposure during the third trimester was associated with increase in birth length by 0.16cm.Conclusions: Prenatal exposure to PM2.5 may be an important risk factor of fetal growth. The first and second trimesters might be the sensitive exposure window. Our findings added new information, and extended our understanding of the risk factors of fetal growth. More studies are needed to explore the mechanisms of PM2.5 affecting fetal growth