ABSORPTION OF NONHEME IRON FROM FOOD DURING NORMAL-PREGNANCY

Objective-To determine whether the increased iron demands of pregnancy could be met by increased absorption from dietary sources. Design and setting-longitudinal prospective study in the research unit of a mate rnity hospital. Subjects-12 normal pregnant women. Interventions-At 12 , 24, and 36 weeks' gestation (within one week) and 16-24 weeks after delivery women ate a breakfast of meat, bread, and orange juice (3.2 m g iron), extrinsically labelled with the stable isotope iron-54 (2.8 m g); the stable isotope iron-57 (200 mu g) was given intravenously. Mai n outcome measures-Serum samples were taken for 10 hours after adminis tration of the isotopes; ratios of the isotopes were measured by induc tively coupled plasma mass spectrometry, and the absorption of oral ir on was calculated. Results-The geometric mean (95% confidence interval ) absorption of iron at 12, 24, and 36 weeks' gestation was 7% (5% to 11%), 36% (28% to 47%), and 66% (57% to 76%) respectively. At 16-24 we eks after delivery the absorption was 11% (6% to 21%). The mean increa se in absorption at 36 weeks (compared with that at 12 weeks) was 9.1 times (6.0 to 13.7). One pregnant woman developed iron deficiency anae mia but was otherwise indistinguishable from the others. Conclusions-A n increase in the absorption of iron from food is a physiological cons equence of normal pregnancy, not the result of developing anaemia duri ng pregnancy, and such an increase is large enough to meet the increas ed requirements of pregnancy provided that the dietary intake is adequ ate.