Maternal iron status influences iron transfer to the fetus

Iron transfer to the fetus may be influenced by maternal iron status. This possibility was examined during the third trimester of pregnancy (33 ± 1 wk gestation) in 37 women living in a peri-urban settlement area of Lima, Peru. Three groups of pregnant women were recruited, Group 1 received no prenatal supplementation. Group 2 received prenatal supplements containing 60 mg of Fe (as ferrous sulfate) and 250 μg of folate, and Group 3 received 60 mg of Fe, 250 μg of folate and 15 mg of Zn (as Zn sulfate) from week 10-24 of pregnancy throughout gestation. On the day of the isotope study, fasted women consumed an oral dose of ⁵⁷Fe (10 mg, as ferrous sulfate) in a flavored sugar drink that did not contain ascorbic acid. Immediately following the PO dose, an i.v. dose of ⁵⁸Fe (0.6 mg) was administered. Cord blood was collected and analyzed for iron isotopes using TIMS. Serum transferrin receptors (sTfR) were measured in maternal blood on the day of isotope dosing. The average percent enrichment (% Enrich.) of the PO and i.v. tracer in the cord blood and maternal sTfR levels are detailed below (mean ± SD). Means within columns with different superscripts significantly differ from one another (p<0.05). Group n Maternal Hb Cord Blood Hb Cord ⁵⁷Fe Cord ⁵⁸Fe Maternal sTfR (g/dl) (g/dl) %Enrich %Enrich (nmol/L) 1 12 10.8±1.0^a 15.0±1.8^a 4.29±0.92^a 13.21±2.13^a 23.7±10.3^a 2 14 11.2±1.3^a 15.6±1.4^ab 2.72±1.42^b 11.64±4.28^a 15.8±4.5^b 3 11 11.2±1.1^a 16.3±1.4^b 2.36±1.41^b 12.58±3.70^a 19.2±9.4^ab Significantly more oral tracer was found in infants born to mothers who did not receive prenatal Fe and cord blood ⁵⁷Fe tracer enrichment was significantly related to maternal sTfR (y= 1.739 + .074X, r²=.191, p<0.01). Iron transfer to the fetus was significantly influenced by maternal iron status.