Micronutrients in pregnancy.

Vitamins and minerals, referred to collectively as micronutrients, have important influences on the health of pregnant women and the growing fetus. Iron deficiency results in anemia which may increase the risk of death from hemorrhage during delivery, but its effects on fetal development and birth outcomes is still unclear. Folic acid deficiency can lead to hematological consequences, pregnancy complications and congenital malformations, but again the association with other birth outcomes is equivocal. Zinc deficiency has been associated in some, but not all studies with complications of pregnancy and delivery, as well as with growth retardation, congenital abnormalities and retarded neurobehavioral and immunological development in the fetus. Iodine deficiency during pregnancy results in cretinism and possible fetal wastage and preterm delivery. Deficiency of other minerals such as magnesium, selenium, copper, and calcium have also been associated with complications of pregnancy, childbirth or fetal development. Deficiencies of vitamins other than folate may likewise be related to such complications; and vitamin A or beta-carotene supplements in pregnancy reduced maternal mortality by 50 % in a controlled trial in Nepal. Additional research is need on the prevalence of such deficiencies and their consequences and on cost-effective public health interventions for their control.