Zinc and pregnancy outcome.

Total zinc needs during the last half of human pregnancy may be approximately 2.6 mg absorbed Zn/d. Adaptations in Zn utilization during pregnancy may help meet those needs. Possible adaptations include an increase in Zn absorption, reduced endogenous Zn loss, redistribution of tissue Zn, and an efficient maternal-fetal Zn transfer. A decline in circulating Zn concentration begins early in pregnancy and continues to term. The effect of gestational stage on circulating Zn should be incorporated into standards for serum Zn of pregnant women. Low maternal serum Zn levels have been associated with pregnancy-induced hypertension, abnormal parturition, and congenital anomalies. In studies done to date, Zn supplementation of 15-45 mg/d failed to improve pregnancy outcome except for a possible reduction in the incidence of a dysfunctional labor pattern. The relationship between Zn status and pregnancy outcome remains an open question.