Changes in iron status during pregnancy in Peruvian women receiving prenatal iron and folic acid supplements with or without zinc

Background: Iron deficiency anemia is the most prevalent nutrient deficienc y during pregnancy, yet there are few data on the effect of prenatal iron s upplementation in women in developing countries. Objective: Our objective was to describe the effect of iron supplementation on hematologic changes during pregnancy, and the effect on those changes o f adding zinc to the supplements. Design: pregnant women were enrolled in a randomized, double-masked study c onducted at a hospital in a shantytown in Lima, Peru. Women were supplement ed daily from 10-24 wk gestation to 4 wk postpartum with 60 mg Fe and 250 m u g folic acid with or without 15 mg Zn. Hemoglobin and ferritin concentrat ions were measured in 645 and 613 women, respectively, at enrollment, at 28 -30 and 37-38 wk; gestation, and in the cord blood of 545 neonates. Results: No differences in iron status were detected by supplement type, bu t hematologic changes were related to initial hemoglobin status. Women with anemia (hemoglobin <110 g/L) showed steady increases in hemoglobin concent ration throughout pregnancy whereas women with relatively higher initial he moglobin concentrations had declining values during mid pregnancy, then ris ing values by 37-38 wk gestation. Women with an initial hemoglobin concentr ation >95 g/L showed increases in serum ferritin by the end of the pregnanc y. Despite supplementation, women with poorer hematologic status; who were younger, single, and multiparous; and who consumed fewer supplements were m ore likely to have anemia at the end of pregnancy. Conclusions: These hematologic changes are congruent with the effects of ir on supplementation reported in placebo-controlled trials and the addition o f zinc did not significantly affect them.