Iron Supplementation During Pregnancy can Reduce the Risk of Low Birth Weight Babies

Pregnancy iron supplement low weight babies

New research published in the recent issue of the British Medical Journal has found that iron supplementation during pregnancy not only reduced the risk of iron deficiency anemia in the mothers but also leads to a reduced risk of giving birth to low birth weight babies. The research was carried out by scientists from the Harvard School of Public Health.

We already know that iron supplementation during pregnancy can improve hemoglobin concentration. However, the effect of supplementation on birth outcomes had not been clearly established. To find out more about this relationship, the researchers carried out a meta-analysis of 8 randomized trials and 44 cohort studies done between 1966 and May 31, 2012. The former involved 17,793 women while the latter included 1,851,682 women. The authors evaluated the effect of iron supplementation, with or without folic acid, on the hemoglobin levels of the mother, associated morbidity and birth outcomes.

First and second trimester of pregnancy

In analyzing the results of the studies, the researchers found that every 10 mg/d increase in iron supplementation (up to a maximum of 66 mg/d) led to a reduction in the risk of maternal anemia by 12%. Moreover, each 10 mg increase in daily iron led to an increase in birth weight by 15.1 g. This was because of the increased levels of maternal hemoglobin. Every 1 g/L increase in maternal mean hemoglobin was associated with a 14.0 g increase in the birth weight.

It was also observed that anemia during the first and second trimester of pregnancy is more likely to be associated with low birth weight and pre-term birth. Daily iron supplementation increased the maternal hemoglobin by 4.59 g/L  as compared to controls and reduced the risk of iron deficiency anemia by 60%.


Iron supplementation during pregnancy reduced the incidence of iron deficiency anemia in mothers as well as the low birth weight of babies.


  1. Haider B, Olofin I, Fawzi W, et al. Anemia, prenatal iron use, and risk of adverse pregnancy outcomes: systematic review and meta-analysis BMJ 2013; 346:f3443