Impact of twice weekly versus daily iron supplementation during pregnancy on maternal and fetal haematological indices: a randomized clinical trial

A randomized clinical trial examined the efficiency and tolerability of twice weekly versus daily iron supplementation during pregnancy. A total of 370 pregnant women were randomly assigned to receive either daily or twice weekly iron supplementation during pregnancy. There were no significant differences in initial and delivery haemoglobin and haematocrit levels between the 2 groups. Ferritin concentrations were significantly lower in the twice weekly group at delivery, but hypoferritinaemia (ferritin 15 μg/L) was not observed in either group. The frequency of nausea, vomiting and constipation were significantly lower in the twice weekly group. Birth weight and length were significantly higher in the daily supplemented group. In non-anaemic mothers, a smaller dose of iron may be sufficient and also might prevent the complications of iron excess.