Daily iron supplementation is more effective than twice weekly iron supplementation in pregnant women in Pakistan in a randomized double-blind clinical trial

In the context of limited effectiveness of iron supplementation programs, i ntermittent iron supplementation is currently under debate as a possible al ternative strategy that may enhance the effectiveness of operational progra ms. This field-based trial assessed the outcome of twice weekly iron supple mentation compared to daily in Pakistan. A double-blind, randomized, clinic al trial was conducted in Northern Pakistan. Anemic pregnant women (n = 191 ) were assigned to receive daily (200 mg ferrous sulfate) or twice weekly ( 2 x 200 mg ferrous sulfate) iron supplementation. Hemoglobin was measured a t baseline and at 4-wk intervals for up to 12 wk. Serum ferritin was measur ed at baseline and 8 or 12 wk. Analysis was by intention to treat. The two groups did not differ in age, parity, sociodemographic characteristics, hem oglobin or serum ferritin concentrations at baseline. Women who received ir on daily had a greater rise in hemoglobin compared with women who received iron twice weekly (17.8 +/- 1.8 vs. 3.8 +/- 1.2 g/L, P < 0.001). The serum ferritin concentrations increased by 17.7 +/- 3.9 <mu>g/L (P < 0.001) in th e daily supplemented group and did not change in the twice weekly group. Da ily iron supplementation remained superior to twice weekly supplementation after controlling initial hemoglobin Z-scores and duration of treatment. Th e body mass index (BMI) modified the effect of daily versus twice weekly ir on supplementation. For every unit increase in BMI, the difference between the two treatment groups was reduced by 0.0014 (final hemoglobin Z-score; P = 0.027). We recommend continuation of daily iron supplementation as oppos ed to intermittent iron supplementation in pregnant women in developing cou ntries.