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Daily prenatal supplement ‘improves birth weight’

Daily prenatal iron supplements ‘substantially’ improves infant birth weight in a dose-response fashion, concludes a new analysis.

The study

US researchers conducted a systematic review and meta-analysis of 48 randomised trials and 44 cohort studies of prenatal iron supplements, including 17,793 and 1,851,682 pregnant women respectively. Outcome measures included haemoglobin iron concentration and birth weight.

The results

Iron supplements increased maternal mean haemoglobin concentration by 4.59g/L and significantly reduced the risk of anaemia and iron deficiency anaemia, relative risks of 0.50 and 0.59 respectively compared with controls. Infant birth weight also increased in a statistically significant linear fashion by 15.1g and the risk of low birth weight decreased in a statistically significant linear fashion by 3% for every 10mg increase in dose/day when compared with the control group. For each 1g/L increase in mean haemoglobin concentration, birth weight increased by 14.0g.

What this means for GPs

The researchers concluded that ‘use of iron in women during pregnancy may be used as a preventive strategy to improve maternal haematological status and birth weight’ and advise that future research should explore ‘feasible strategies’ to do this.

BMJ 2013, online 21 June


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