Yonago Acta medica 1996;39:65-71

Reduced Zinc Levels in Pregnant Women with Premature Rupture of Membrane and Preeclampsia

Takako Maeda and Toshiyuki Tanaka

Tottori University College of Medical Care Technology, Yonago 683, Japan

Zinc is a trace element essential to normal human growth and development, and plays an important role in human reproduction. We measured the levels of zinc in maternal serum, umbilical cord venous serum, amnion and neonatal scalp hair in 76 mothers and their babies, and analyzed the results obtained. The level of zinc was significantly (P < 0.01) correlated between maternal serum and cord serum (r=0.476), and between neonatal hair and each of amnion (r=0.438), maternal serum at 36 weeks' gestation (r=0.387) and cord serum (r=0.482). There was a decreasing tendency in birth weight along with the decrease of zinc in maternal serum at 36 weeks' gestation. When pregnant women were classified into 2 groups of premature rupture of membrane (PROM) and normal labor, the PROM group showed significantly lower zinc levels in maternal serum at 36 weeks' gestation, cord serum, amnion and neonatal hair than the normal group. When the subjects were classified into 2 groups of preeclamptic and healthy pregnant women, the preeclamptic group showed significantly lower zinc levels in cord serum, amnion and neonatal hair than the healthy group; but difference in maternal serum was not significant between the groups. Comparison of birth weight showed a significant difference between the PROM and normal groups, but not between the preeclamptic and healthy groups. These findings show that decreased zinc levels in pregnancy might be related with the onset of PROM and low birth weight. We considered that fetal growth is presumably inhibited by maternal zinc deficiency, which is known to inhibit immunological capabilities, and inferred that maternal zinc deficiency might have inhibited immunological capabilities in both mother and fetus. Under these conditons, the risk of amniotic infections would be enhanced and the onset of PROM might result. Our observations suggest a further necessity to investigate the role of zinc in maintenance of normal pregnancy.

Key words: fetus; preeclampsia; pregnant women; premature rupture of membrane; zinc level