Taking iron daily during pregnancy is associated with a significant increase in birth weight and a reduction in risk of low birth weight, according to UK and US researchers.
Their study, published online in the BMJ, analysed the results of over 90 studies, involving nearly two million women.
For every 10mg increase in iron dose per day – up to 66 mg per day – risk of maternal anaemia was 12% lower, birth weight increased by 15g and risk of low birth weight decreased by 3%.
Janet Fyle, professional policy advisor at the Royal College of Midwives, said serious iron deficiency tended to affect low income countries.
But she added: “Ensuring that pregnant women have the optimum level of iron is important, so this research is useful. There is an expectation that some women’s haemoglobin levels may drop a little during pregnancy and this is normal.”