Iron deficient anemia affects 38% of pregnant women around the world and is clearly one of the reasons prenatal iron supplements are recommended. Researchers in this systematic review and meta-analysis analyzed 48 randomized trials of iron supplementation, involving 17,793 women and 44 cohort studies of maternal anemia and birth outcomes involving 2 million women.
Iron supplementation was associated with a significant reduction in risk for low birth weight in the randomized trials. However, iron supplementation did not have a significant effect on the risk for preterm birth or small for gestational age births. In the other studies, first or second trimester iron deficient anemia was associated with significantly higher risk for babies with low birth weight.
Commentary: Iron deficient anemia is one of the simplest conditions to test for and diagnose, and simple and inexpensive to treat. It should especially be treated during pregnancy due to the potential impact on the birth weight, size, and preterm births. There are of course other key supplements that determine a healthy pregnancy, developing fetus and infant. These include, but are not limited to folic acid, omega-3 fatty acids from fish oil, probiotics, and more. Some women will acquire nausea from iron supplements. This can often be mitigated by taking iron in some different forms that are easier on the digestive tract including iron aspartate, ferrous succinate and ferrous fumarate. In addition, taking the iron with vitamin C enhances iron absorption and taking iron with food tends to minimize or even bypass nausea, constipation, or gas, a frequent occurrence with iron supplements.
Haider B, et al. Anaemia, prenatal iron use, and risk of adverse pregnancy outcomes: Systematic review and meta-analysis. BMJ 2013 June 21:346.