A Study on the Placental Transfer of Mercury in Pregnant Women @bullet'— §oeöšqoe¤‹ †@bulletššâ‹«@bulletûoe'@bullet " ' † –ì " Ä @bullet
نویسنده
چکیده
To clarify the maternal-fetal transfer of mercury across the placenta, inorganic and organic mercury were determined in 41 paired samples of maternal blood, placenta, umbilical cord blood and umbilical cord obtained from pregnant women who had no particular exposure to mercury compounds in their history. Both inorganic and organic mercury were detected in all the samples but the ratio of organic mercury to total mercury concentrations was much higher than that of inorganic mercury to total mercury. The concentrations of inorganic and organic mercury in the umbilical cord blood were significantly higher than those in the maternal blood, strongly indicating the maternal-fetal transfer of mercury via placenta. The ratio between placental concentration and maternal blood concentration of the two mercury forms was significantly higher in the inorganic than in the organic form, indicating that inorganic mercury does preferentially accumulate in the placental tissues. On the other hand, the ratio between umbilical cord blood concentration and placental concentration of the two mercury forms was significantly higher in the organic than in the inorganic forms, indicating that there was a preferential transfer of the organic mercury across the placenta. In addition, no significant difference was observed between the forms of mercury regarding the ratio of umbilical cord blood concentration to maternal blood concentration, suggesting a possibility that both forms of mercury may be transferred to the fetus with similar efficiency. However, the correlations between maternal blood and umbilical cord blood, between maternal blood and placenta and between placenta and umbilical cord blood in terms of the concentrations of the two forms of mercury suggest that the placenta is less permeable to inorganic mercury and that the organic mercury reaching the fetus through the transplacental route may be metabolized into an inorganic form.
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