Serum zinc binding capacity in pregnant women

Zinc is an important element during the prenatal period. Since plasma zinc levels are not directly related to the nutritional status of this metal in pregnant women, we designed this study to find out if plasma protein zinc binding capacity is a more reliable parameter than total serum zinc to establish zinc nutritional status during pregnancy. We analyzed total serum zinc and zinc binding capacity in 84 normal pregnant women and in 14 nonpregnant women. Within pregnant women, samples were classified according to the gestational age. Total zinc serum was significantly decreased in pregnant women as compared to control ones. The decrease in zinc occurred slowly during the whole period of pregnancy; a negative correlation was found between serum zinc and gestational time. Protein zinc binding capacity was found to be significantly higher in pregnant women than in the control ones. This parameter was positively correlated to total serum zinc in pregnancy. We conclude that since the protein zinc binding capacity increases with advancing gestation, pregnant women take advantage of this to maintain the levels of serum-free zinc, transferable to the fetus.