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Background: Essential and non-essential metal exposure during pregnancy is ubiquitous, influencing maternal and child health. We evaluated associations of prenatal metals with mitochondria DNA abundance (mtDNA) and telomere length (TL) in mothers during pregnancy and their children at birth, as biomarkers of oxidative stress and inflammation. Methods: We measured six nonessential metals (As, Ba, Cd, Cs, Hg, Pb) and four essential metals (Mg, Mn, Se, Zn) in first trimester red blood cells from women in Project Viva, a prospective pre-birth cohort in Massachusetts. We measured mtDNA and TL in second trimester maternal blood (N=893-898) and cord blood (N=408-419). We used multivariable linear regression models and Bayesian Kernel Machine Regression (BKMR) to evaluate their associations, adjusted for confounders. Results: Mean (SD) mtDNA was 1.05 (0.32) in maternal blood and 1.01 (0.25) in cord blood. Mean (SD) TL was 0.68 (0.24) in maternal and 1.24 (0.70) in cord blood. In adjusted models, a two-fold increase in maternal magnesium was associated with decreased maternal mtDNA (β -0.09, 95% CI: -0.15, -0.03) and cord blood mtDNA (β -0.08, 95% CI: -0.14, -0.01). A two-fold increase in maternal lead was associated with increased maternal mtDNA (β 0.04, 95% CI: 0.01, 0.06). Selenium was associated with increased cord blood TL (β 0.26, 95% CI: 0.0, 0.52). When characterizing the overall effect of the mixtures, our BKMR analyses suggested a dose-response association between the metal mixture and cord blood mtDNA relative to the 50^th percentile (25^th percentile of mixture β 0.08, 95% CI: -0.05, 0.20; 75^th percentile of mixture β -0.11, 95% CI: -0.25, 0.03). Conclusion: Our findings suggest that certain prenatal metals are associated with molecular biomarkers of oxidative stress and inflammation in both maternal second trimester and cord blood, and future work will evaluate the extent to which these markers are associated with health outcomes.