Umbilical Cord Tissues as Matrices to Predict Prenatal Exposure to Mercury - Review - Abstract
Mercury prenatal exposure can be estimated through mercury concentrations in different maternal/fetal biological matrices. However, questions have been raised regarding the accuracy of umbilical cord matrices as biomarkers of that exposure. The aim of the present study was to verify the potential of umbilical cord matrices as prenatal exposure biomarkers to mercury and their uses in studies of correlation and association with outcome at birth and with neurodevelopment. For such, we have searched different databases for primary scientific articles using the following terms: methylmercury/total mercury and umbilical cord blood, methylmercury/total mercury and umbilical cord tissue; methylmercury/total mercury in umbilical cord and child growth/neurodevelopment. We found 55 articles about that topic, but only 34 articles met the following inclusion criteria. In general, the studies showed that concentrations of total mercury and methylmercury in umbilical cord blood were higher than those found in maternal blood and umbilical cord tissue and that cord
tissue concentrations were better correlated with cord blood concentrations than maternal blood concentrations. Methodological differences among the studies were found regarding the collection of umbilical cord blood and the processing of the cord tissue samples for analysis. In the majority studies that used these matrices as mercury, exposure biomarkers have not verified association with anthropometrics or neurodevelopment. Factors inherent to the placenta and differences in the collection and analysis methods among the studies analyzed may explain the uncertainties regarding the definition of the best biomarker of prenatal exposure to mercury.