In an ongoing, prospective observational study in women undergoing transvaginal radiofrequency ablation of uterine fibroids, six out of ten women included, so far, have presented with anemia (mean Hb 10.3 g/dL) and received perioperative oral SI (30 mg elemental iron/day) up to at least 30 days after the procedure. This evidence concerns the gene GSTM1 and anemia.