The need for maternal zinc supplementation in developing countries: an unresolved issue.

Maternal zinc deficiency during pregnancy has been related to adverse pregnancy outcomes. Most studies in which pregnant women have been supplemented with zinc to examine effects on pregnancy outcome have been carried out in industrialized countries and the results have been inconclusive. This review discusses preliminary findings of eight randomized, controlled intervention trials performed recently in less-developed countries. It is based on evidence presented by investigators and discussed during a workshop held in Wageningen, The Netherlands in June 2001. Preliminary findings from these studies indicate maternal zinc supplementation has a beneficial effect on neonatal immune status, early neonatal morbidity and infant infections. With respect to labor and delivery complications, gestational age at birth, maternal zinc status and health and fetal neurobehavioral development, evidence is conflicting and more research is required. Data currently available do not support the hypothesis that maternal zinc supplementation promotes intrauterine growth. Thus despite the emerging evidence for a positive effect of zinc on some outcomes of pregnancy, the workshop concluded that the full results of studies carried out need to be known and that more research is required to determine the benefits of large-scale introduction of zinc supplementation of pregnant women in less-developed countries.