Consistent with the association between plasma 25(OH)D and Hb, we only found that VD deficiency in T1 (OR = 1.68, 95% CI: 1.20–2.34) and T2 (OR = 2.02, 95% CI: 1.27–3.22) was significantly associated with a higher risk for anemia after the 25(OH)D measurement among those who received iron supplements during pregnancy (Table 5). This evidence concerns the gene GSTM1 and anemia.