ObjectiveTo review the evidence about universal iron supplementation in pregnancy to prevent maternal anemia.MethodsBibliographic research of randomized and controlled clinical trials, meta-analyses, systematic reviews, and clinical guidelines, published between August 2009 and August 2019, using the MeSH terms:iron;therapeutic use;pregnancy;anemia,preventionandcontrol.ResultsWe included six clinical guidelines, three meta-analyses and one randomized controlled clinical trial.DiscussionMost articles point to the improvement of hematological parameters and reduction of maternal anemia risk, with supplementary iron. However, they do not correlate this improvement in pregnant women without previous anemia with the eventual improvement of clinical parameters.ConclusionUniversal iron supplementation in pregnancy is controversial, so we attribute a SORT C recommendation strength.