Examination of Trace Metals and Their Potential Transplacental Transfer in Pregnancy

Abstract

With the ever-growing concern for human health and wellbeing, the prenatal period of development requires special attention since fetuses can be exposed to various metals through the mother. Therefore, this study explored the status of selected toxic (Pb, Cd, Ni, As, Pt, Ce, Rb, Sr, U) and essential trace metals (Mn, Co, Cu, Zn, Se) in the umbilical cord (UC) sera, maternal sera, and placental tissue samples of 92 healthy women with normal pregnancies. A further aim focuses on the potential transplacental transfer of these trace metals. Based on the obtained levels of investigated elements in clinical samples, it was observed that all of the trace metals cross the placental barrier and reach the fetus. Furthermore, statistical analysis revealed significant differences in levels of toxic Ni, As, Cd, U, Sr, Rb, and essential Mn, Cu, and Zn between all three types of analyzed clinical samples. Correlation analysis highlighted As to be an element with levels that differed significantly between all tested samples. Principal component analysis (PCA) was used to enhance these findings. PCA demonstrated that Cd, Mn, Zn, Rb, Ce, U, and Sr were the most influential trace metals in distinguishing placenta from maternal and UC serum samples. As, Co, and Cu were responsible for the clustering of maternal serum samples, and PCA demonstrated that the Pt level in UC sera was responsible for the clustering of these samples. Overall, the findings of this study could contribute to a better understanding of transplacental transfer of these trace metals, and shed a light on overall levels of metal exposure in the population of healthy pregnant women and their fetuses.

Placental Barrier on Cadmium Transfer from Mother to Fetus in Related to Pregnancy Complications

“…Compared with other studies, the concentrations of Cd in maternal blood, placenta, and umbilical cord blood in Kunming, China were higher than those in Slovenia, 18 Germany (Saudi), 19 Sweden, 20 and Beijing and Zhejiang, China, 21,22 but the concentrations of Cd in maternal blood and umbilical cord blood in Kunming, China were lower than those in Catalonia, Spain 23 and Brazil (Rio de Janeiro). 24 Studies in other regions of the world have reported that the content of Cd in the placenta is higher than that in maternal blood and umbilical cord blood, [25][26][27] which is consistent with our results. As a temporary multifunctional organ connecting the mother and fetus, 28 the placenta plays an important role in filtering and blocking harmful substances.…”

Prenatal Cadmium Exposure and Maternal Sex Steroid Hormone Concentrations across Pregnancy

“…Additionally, these mechanisms may differ considerably from other environmental exposures, given that in contrast to many other toxicants, relatively little cadmium crosses the placenta to directly impact the fetus in animals and human studies; instead, the placenta highly concentrates cadmium [ 13 , 14 , 15 , 16 ]. This results in cadmium levels in placental tissue being four times higher than cadmium levels in maternal serum and six times higher than cadmium level in umbilical cord serum [ 17 ].…”