Association between magnesium, calcium, phosphorus, copper, and zinc in umbilical cord plasma and erythrocytes, and the gestational age and growth variables of full-term newborns

Abstract

We determined reference values in umbilical cord plasma and erythrocytes for magnesium, total calcium, phosphorus, copper, and zinc, and then calculated correlations and stepwise-regression equations in 66 white full-term new-born infants (35 boys, 31 girls). Only infants meeting certain optimal criteria and benefiting from excellent maternal conditions and uncomplicated pregnancies were included. There were no significant sex-related differences at birth among the variables studied. Gestational age was positively correlated with erythrocyte zinc (P <0.001), and plasma calcium was positively correlated with erythrocyte copper (P <0.001). Plasma copper proved to be the most significant variable in the stepwise-regression equation for birth height as the dependent variable. The most significant regressors accounting for birth weight were erythrocyte zinc followed by plasma zinc.