LAUSR

Prenatal exposure to particulate matter (PM) in ambient air has been linked to changes in newborn mitochondrial DNA copy number (mtDNAcn), but the effects of exposure are inconsistent. We aimed to investigate the effect of weekly PM exposure during pregnancy on newborn mtDNAcn. The present study included 762 mother-infant pairs who were recruited in a birth cohort established between November 2013 and March 2015 in Wuhan, China. Mother's prenatal daily exposure to PM2.5 and PM10 was calculated using a spatial-temporal land use regression model. Relative mtDNAcn in cord blood leukocytes was determined by quantitative real-time polymerase chain reaction. Distributive lag regression models (DLMs) were applied to estimate the association between PM exposure and newborn mtDNAcn. In the adjusted models, prenatal PM2.5 exposure during 25-32 weeks and PM10 exposure during 25-31weeks were significantly associated with decreased cord blood mtDNAcn. PM2.5 exposure during the third trimester was related to decreased mtDNAcn (cumulative percent change: -8.55%, 95% CI: -13.32%, -3.51%). We also identified other exposure windows (17-22 and 11-22 weeks) in which PM exposure was positively associated with mtDNAcn. Overall, exposure to particulate air pollution during mid-to-late gestation is significantly associated with alterations in newborn mtDNAcn, potentially suggesting an enhanced sensitivity to PM exposure during this period.