Sample size determination
The sample size was calculated using G power 3.1.9.2 with an assumptions of a precision of 5%, power of 85%, effect size of 0.5 and mean hemoglobin change of 0.8gm/dl over the study period [Since cluster sampling was used, the calculated sample size was multiplied by design effect of two. Considering a 10% non-response rate and 20% loss through follow up and drop out, the final sample size was 224 pregnant women in both arms. Therefore, 366 women who fulfilled the requirement were enrolled to the trial in intervention and control arm.