The impact of different doses of oral iron supplementation during pregnancy: a pilot randomized trial

Abstract

The burden of iron-deficiency anemia remains significant during pregnancy. Oral iron is first-line medication, but there is uncertainty about a range of factors including adherence and side-effects of different doses. We conducted a pilot randomized trial to investigate the impact of different doses of oral iron supplementation started early in pregnancy, in non-anemic women, for four main outcomes; recruitment and protocol compliance, adherence, maintenance of maternal hemoglobin and side-effects. Participants at antenatal clinic visits were allocated to one of three trial arms, in a 1:1:1 ratio, as 200mg ferrous sulphate daily, alternate days or three-times per week, with follow-up to delivery. Baseline characteristics of 300 recruited participants were well matched between trial arms. The mean proportion of tablets taken as expected per participant was 82.5% overall (72.3%, 89.6% and 84.5% for the daily, alternate days and three-times a week arm, respectively). There was a lower overall adherence rate in the daily arm (47%) compared with alternate days (62%) and three times per week (61%). Reduction in hemoglobin between randomization and 28 weeks appeared smaller for the daily arm. A range of side-effects were commonly reported at baseline before starting interventions, and by later antenatal visits. Many side effects of iron overlapped with normal pregnancy symptoms. A daily iron dosing schedule might give the best opportunity for delivering an adequate iron load during pregnancy in non-anemic women. Further randomized trials powered on clinical outcomes are needed to establish the clinical effectiveness of oral iron supplementation to prevent iron deficiency anemia. (ISRCTN12911644).