The data comparing daily versus intermittent iron supplementation during pregnancy remain controversial. This study was undertaken to compare the efficacy of daily versus two different intermittent iron supplementation regimes on hematologic markers and birth outcomes in nonanemic pregnant women.
Two hundred and ten women with singleton pregnancies, no known disease, and hemoglobin levels >11.0 g/dL were randomly assigned to one of three groups, ie, Group A consuming two iron supplementation tablets once weekly (100 mg iron per week, n = 70), Group B consuming one tablet twice weekly (100 mg iron per week, n = 70) and Group C, consuming one tablet daily (50 mg iron per day, n = 70). No additional micronutrients were supplied. Hemoglobin and serum ferritin levels were measured at 20, 28, and 38 weeks. Pregnancy and birth outcomes (pregnancy termination, method of delivery, birth weight, stillbirth) were analyzed.
In total, 201 women completed the protocol. There was a significant difference in mean hemoglobin and ferritin levels in Group B at 38 weeks ( P = 0.018 and P = 0.035, respectively) but this difference was not clinically significant (hemoglobin >12 g/dL, ferritin >19 μg/L). There was a significant increase in ferritin in Group C ( P = 0.03) at 28 weeks. No significant difference was observed with respect to pregnancy or birth outcome across the groups. All regimens prevented the occurrence of hemoglobin <10.5 g/dL, but weekly supplementation was associated with development of a hemoglobin level <11.0 g/dL (risk ratio 0.044).