GSTM1 and anemia (phenotype): Moreover, in Stratum 1, when the regression models were performed separating women with and without ID on week 12 (Table 4), we observed that only in women with ID, the dose of 80 mg/d instead of 40 mg/d increased Hb levels in the third trimester (β: 8.81; SE: 2.40; p = 0.001), protecting women against anemia and IDA (OR: 0.03; 95%CI: 0.01–0.60; p = 0.021, for both cases).