A randomised placebo‐controlled trial to determine the effect of iron supplementation on pregnancy outcome in pregnant women with haemoglobin ≥ 13.2 g/dl

Objective To study the effect of iron supplementation on pregnancy outcome in pregnant women with haemoglobin (Hb) ≥13.2 g/dl. Design A randomised, double‐blind, placebo‐controlled trial. Setting Routine health services. Population Seven hundred and twenty‐seven pregnant women with Hb ≥13.2 g/dl in the early stage of the second trimester. Methods Each woman took one tablet of 50 mg of ferrous sulphate daily in the case group ( n = 370) or placebo in the control group ( n = 357) throughout pregnancy. Main outcome measures Pregnancy outcome. Results While there were no significant differences in demographic and obstetric characteristics between the two groups before any intervention, small‐for‐gestational‐age birth rate and the number of women with hypertension disorder increased significantly in the case group in comparison with the control group (57 15.7% versus 36 10.3%, P = 0.035, 10 2.7% versus 3 8%, P = 0.05, respectively). Conclusions Our finding proves that routine iron supplementation in nonanaemic women is not rational and may be harmful.