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Effect of low-dose versus higher-dose antenatal iron supplementation on child health outcomes at 36 months of age in Viet Nam: longitudinal follow-up of a cluster randomised controlled trial
  1. Sarah Hanieh1,
  2. Tran T Ha2,
  3. Julie A Simpson3,
  4. Sabine Braat3,
  5. Tran T Thuy2,
  6. Thach D Tran2,4,
  7. Janet King5,
  8. Tran Tuan2,
  9. Jane Fisher4,
  10. Beverley-Ann Biggs1,6
  1. 1Department of Medicine, University of Melbourne, Peter Doherty Institute for Immunity and Infection, Parkville, Victoria, Australia
  2. 2Research and Training Centre for Community Development, Hanoi, Viet Nam
  3. 3Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
  4. 4The Jean Hailes Research Unit, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
  5. 5Children’s Hospital Oakland Research Institute, Oakland, California, USA
  6. 6The Victorian Infectious Diseases Service, Royal Melbourne Hospital, Parkville, Victoria, Australia
  1. Correspondence to Sarah Hanieh; shanieh{at}


Introduction Intermittent iron-folic acid supplementation (IFA) is currently recommended for pregnant women in populations where anaemia prevalence among pregnant women is <20% or if daily iron is not acceptable. The effect of providing lower doses of antenatal elemental iron through intermittent regimes on longer-term health outcomes in childhood is unclear.

Methods A prospective cohort study conducted between May 2012 and May 2014 in Viet Nam among children of 36 months of age, born to women previously enrolled in a cluster randomised controlled trial of antenatal micronutrient supplementation (daily IFA (60 mg elemental iron) vs twice-weekly IFA (60 mg elemental iron) vs twice-weekly multiple micronutrient (MMN) supplementation (60 mg elemental iron)). Primary outcomes were height-for-age z-scores (HAZ), according to WHO growth standards and cognitive composite scores (Bayley Scales of Infant and Toddler Development, third edition) at 36 months of age.

Results A total of 1017 children born to mothers enrolled in the cluster randomised trial were assessed at 36 months of age. Adjusted mean differences (MDs) in HAZ were –0.14 (95% CI –0.28 to –0.01) and –0.15 (95% CI –0.29 to –0.01) in children born to mothers who received twice-weekly IFA or MMN compared with those who received daily IFA. Children born to mothers who received twice-weekly MMN had lower composite motor scores compared with those who received daily IFA (MD –2.07, 95% CI –4.11 to –0.03). There were no differences in composite cognitive scores in the twice-weekly compared with daily regimens.

Conclusions Low-dose antenatal IFA supplementation (120 mg elemental iron per week) resulted in lower HAZ and motor composite scores in children compared with higher-dose antenatal IFA supplementation (420 mg elemental iron per week). This highlights the importance of adequate iron stores during pregnancy and the need for careful monitoring when lower-dose antenatal iron regimens are used.

Trial registration number Australia New Zealand Clinical Trials Registry: 12610000944033.

  • Maternal health
  • nutrition
  • child health
  • public health

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  • Contributors SH analysed the data, prepared the results and wrote the first and subsequent drafts of the manuscript. SH, B-AB, TTH and JF designed the study. SH, TTH and SB managed the data set and performed the statistical analysis. TTT, TDT, TTH, JAS and JK contributed to the study and survey design, reviewed and commented on the drafts of the report. TTH and TTG facilitated the conduct of the survey at the commune health stations. All authors approved the final submitted version of the manuscript. SH had full access to all the data in the study and assumes final responsibility for the decision to submit for publication.

  • Funding The original cluster randomised trial was funded through a grant from the National Health and Medical Research Council of Australia (grant number 628751).

  • Disclaimer The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.

  • Competing interests SH is funded by an Australian National Health and Medical Research Council (NHMRC) Early Career Fellowship 1112581. JAS is funded by an Australian National Health and Medical Research Council (NHMRC) Senior Research Fellowship 1104975.

  • Ethics approval The Melbourne Health Human Research Ethics Committee and the Ha Nam Provincial Human Research Ethics Committee.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement No additional data are available.

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