Maternal and foetal nutritional requirements are exceptionally high during pregnancy to meet the associated physiological and metabolic demands. As is the case for many nutrients, cobalamin stores in foetal tissues are established during pregnancy. Current cobalamin requirements during pregnancy are based on estimates of the total amount of cobalamin assumed to accumulate in the foetal liver from studies published between 1962 and 1975. Pregnancy cobalamin intake recommendations are based on studies that used maternal plasma or serum total cobalamin or urinary methylmalonic acid excretion in the child as markers of cobalamin insufficiency. Cobalamin deficiency is highly prevalent in countries like India due to the widely practised vegetarian diet. Recent studies using functional markers of cobalamin status such as plasma holotranscobalamin (holoTC) and methylmalonic acid (MMA) during pregnancy, lactation and early life have shown that suboptimal cobalamin intake and status also affects women with omnivorous diets in industrialised countries. Many studies have shown that low cobalamin status is associated with birth defects and developmental problems in the children. However, cobalamin supplementation during pregnancy and lactation has received relatively little attention compared to folic acid supplementation.