Further observations on the relation between iron and folate status in pregnancy

This study was planned to determine whether iron deficiency in pregnancy predisposed to the development of folate deficiency and also the smallest daily iron supplement that maintained haemoglobin levels in pregnancy.Three groups of women were given oral ferrous fumarate supplying 30, 60, and 120 mg of iron; a fourth group was given 1 g of parenteral iron in early pregnancy followed by oral iron (60 mg); a fifth group received a placebo. Tablets were taken once daily.Oral iron 30 mg once daily maintained haemoglobin levels throughout pregnancy. Women whose marrows lacked demonstrable iron at the 37th week had a significantly higher incidence of megaloblastic haemopoiesis (28.7%) than those with demonstrable iron stores (15.3%); women taking oral iron did not have a lower frequency of megaloblastosis than those given a placebo. We concluded that iron does not have a direct effect on folate status in pregnancy, that the association of iron deficiency and megaloblastic anaemia in pregnancy is the result of poor nutrition, and that there is no cause-and-effect relation between them.