BACKGROUND: Maternal exposure to toxic and essential elements can be transferred to the fetus. Deciduous tooth dentine, formed prenatally, serves as a potential biomarker for fetal exposure. OBJECTIVE: To investigate the relationship between maternal blood Pb, Mn, Cu, Mo and Zn element concentrations and the corresponding child tooth dentine levels in mid pregnancy. A secondary objective explores the predictive value of maternal blood element concentrations for child dentine element levels for the same metals. METHODS: Early-life element concentrations were measured in maternal whole blood from the 2nd trimester and in child tooth dentine from 94 child-mother dyads enrolled in the Norwegian Mother, Father and Child Cohort Study (MoBa), The Norwegian Environmental Biobank (NEB) and the MoBaTooth biobank. The relationship between lead (Pb), manganese (Mn), copper (Cu), molybdenum (Mo) and zinc (Zn) in maternal blood and child dentine was examined using correlations and Receiver Operating Characteristic (ROC) curves. RESULTS: Maternal blood Pb concentration and child dentine Pb in 2nd trimester-average correlated strongly for both girls and boys (r = 0.58, p <
0.001 and r = 0.51, p <
0.001) and was able to predict child dentine Pb. Cu correlated negatively between mothers and boys (r = -0.35, p <
0.001), and with borderline significance for girls (r = -0.17, p = 0.058). For Mn, Mo and Zn the associations between maternal blood and child dentine were less clear and differed by child sex. CONCLUSION: Our analysis confirmed a strong association between maternal blood Pb concentration and child tooth dentine Pb. These findings offer a promising biomarker of early life exposure and may help to identify consequences of maternal exposure during pregnancy.