We have previously described that women who have pregestational obesity experience “obesity hypoferremia” during pregnancy [14]; an iron deficiency phenotype which simultaneously features the hallmarks of iron deficiency, including decreased serum iron and higher soluble transferrin receptor (sTfr) concentrations, as well as signs of anemia of chronic disease (ACD) such as unaltered ferritin and hemoglobin concentrations [3]. This evidence concerns the gene TFRC and obesity due to melanocortin 4 receptor deficiency.