Transferrin saturation was lower in women with obesity at 12 and 28 GW (12 GW 23.9%, 24.5%, 30.3%, P = 0.016; 28 GW 13.2%, 17.7%, 17.2% P < 0.001, obesity, overweight, and normal weight, respectively). This evidence concerns the gene TF and obesity due to melanocortin 4 receptor deficiency.