McCarthy et al. [40] analyzed 645 pregnant women without anemia recruited in the first trimester and followed up at 15, 20, and 33 GW, with similar prevalence rate and supplementation to the current analysis (ferritin <15 μg/L: 4.5%, 51.2%; ferritin <30 μg/L: 20.7%, 83.8% at 15 and 33 GW respectively); they found that obesity was not associated with ID, whether defined by ferritin (<12, <15, <30 μg/L) or by sTfR > 4.4 mg/L. The gene discussed is TFRC; the disease is obesity due to melanocortin 4 receptor deficiency.