Zinc, pregnancy and parturition.

The role of zinc in the nutrition of pregnant women and its relations to prenatal growth and parturition are reviewed. Zinc deficiency (ZD) affects fetal growth and development both in experimental animals and in man. The teratogenicity of zinc deficiency was widely demonstrated in animals and is also evident in humans. Alcohol intoxication potentiates the effects of ZD in animals. Plasma zinc levels decrease during pregnancy and apparently an adequate and continuous intake of zinc is required for a normal embryonic development. The zinc content of amniotic fluid seems to be related with fetal growth but its value as an indicator of embryonic development is controversial. Zinc deficiency also affects adversely parturition. Mild zinc deficiency may affect a large number of pregnant women, being potentially harmful to the mother and the fetus. This situation requires the screening of high-risk groups, the definition of adequate dietary intakes for each population, and the supplementation with zinc when deficits are detected.