Blood of my blood: maternal health and diet inferred from high-resolution histology-driven, biogeochemical analysis of prenatal deciduous tooth enamel

Deciduous teeth start forming early during pregnancy and the enamel that develops during the intrauterine period permanently records information encompassing the mother’s dietary habits, environment and potential physiological stresses during pregnancy. Indeed, the study of human prenatal dental enamel provides a wealth of information about the early moments of the mother-infant dyad. However, despite the great potential offered by the study of prenatal enamel, this field remains under- explored. The present work aims to investigate the diachronic evolution of the mother-infant dyad taking advantage of an integrated approach involving high-temporal resolution histological and biogeochemical analyses using laser-coupled mass spectrometry (LA- ICPMS) on the prenatal enamel of 41 deciduous teeth selected from contemporary (n=13) and modern (n=15) individuals with known life histories, as well as from archaeological contexts (n=13). Histological results report enamel growth trajectories and crown formation times, but also the timing of physiological stresses expressed in the enamel as Accentuated Lines. The combination of histological and biogeochemical analyses can detect changes in trace element patterns throughout the individual’s gestational life. Strontium (Sr), Barium (Ba) and Magnesium (Mg) are used as proxies for maternal diet allowing the estimation of the mother’s trophic level during the last months of pregnancy. Moreover, the presence of heavy metals such as lead (Pb) can provide information on the mother's potential exposure to pollutants and their incorporation by the foetus during gestation. This work offers a novel and nuanced view of the mother-infant nexus, not limited to the development and health of the infant, but also inferring on the mother’s life, health and diet during pregnancy, as derived from the infant’s prenatal dental tissue.