[Study on maternal-fetal status of Pb, Cd, As, Hg, Mn and Se elements and transplacental transfer efficiency]

Objective: To understand the levels of Pb, Cd, As, Hg, Mn, and Se in maternal and umbilical cord blood, and to explore the transplacental transfer efficiency (TTE). Methods: From September 2010 to December 2013, a total of 773 pregnant women and their newborns (Laizhou Bay Birth Cohort) were recruited from a second grade hospital in the south bank of Laizhou Bay, Bohai, Shandong Province. According to different detection methods, the six measured elements are classified into three groups including the Hg measurement group (595 mother-newborn pairs), the Pb measurement group (534 mother-newborn pairs), and the Cd, As, Mn and Se measurement group (244 mother-newborn pairs). The demographic characteristics of pregnant women and their newborns were obtained by the questionnaire. The concentrations of elements in maternal and umbilical cord blood were detected and the TTE of each element (elemental concentration in cord blood/elemental concentration in maternal blood) was calculated. The correlation of elements between maternal and cord blood was analyzed using Spearman's rank correlation coefficient. Results: The mean±SD of maternal age, gestational week and newborn birth weight of 773 mother-infant pairs were (28.34±4.50) years, (39.47±1.39) weeks and (3 419.47±497.39) g respectively. The median concentrations of Pb, Cd, As, Hg, Mn and As in maternal and cord blood were 31.12 and 30.02, 1.19 and 0.47, 8.05 and 6.03, 0.69 and 1.26, 100.70 and 105.55, 127.25 and 115.00 μg/L, respectively. The TTE of Pb, Cd, As, Hg, Mn, and Se was 0.98, 0.41, 0.73, 1.73, 0.96 and 0.91, respectively. Pb, Cd, Hg, Mn, and Se showed a significant positive correlation between maternal blood and cord blood, with Spearman correlation coefficients of 0.397, 0.298, 0.698, 0.555, and 0.285 (all P values<0.001). Conclusion: Each element was commonly detected in maternal blood and cord blood. The TTE of Hg was the highest.