Profile of trace element concentrations in the feto-placental unit in relation to fetal growth

Background. During pregnancy, trace elements are indispensable for life maintenance not only for the mother but also for the fetus. The purpose of this study was to examine whether fetal growth is associated with altered levels of trace elements in maternal blood, fetal blood, and placenta tissue. Methods. Twenty‐one pairs of healthy mothers and their newborns with intrauterine growth restriction delivered after 34 weeks of gestation were recruited for the study. In addition, 30 pairs of healthy mothers and their appropriate for gestational age newborns were included as controls. Maternal venous blood, umbilical cord venous and arterial blood, and placenta tissue were collected immediately after delivery. Six essential elements, magnesium, manganese, iron, copper, zinc, and selenium, and four other elements, rubidium, strontium, cadmium, and cesium, in those samples were determined by inductively coupled plasma mass spectrometry or inductively coupled plasma atomic emission spectrometry. Results. Compared with appropriate for gestational age cases, intrauterine growth restriction cases showed higher magnesium, copper, and selenium concentrations in umbilical cord arterial sera, and higher magnesium and selenium concentrations in placenta tissue, but no significant differences appeared for the elements measured in maternal and umbilical cord venous sera. The umbilical cord venous vs. maternal sera concentration ratio was elevated for copper, and the umbilical cord arterial vs. umbilical cord venous sera concentration ratios were elevated for copper and zinc, but there were no differences in placenta tissue vs. maternal sera concentration ratios in intrauterine growth restriction cases. Conclusions. Among the trace elements evaluated, magnesium, copper, zinc, and selenium showed elevated concentrations in umbilical cord arterial blood, or elevated umbilical cord arterial vs. umbilical cord venous blood concentration ratios in intrauterine growth restriction cases. Reduced consumption efficiency of these four essential trace elements may be closely associated with retarded fetal development.