We found that Hb taken at 24–30 gestational weeks as well as infrequent iron supplement use were independent risk factors for anemia at delivery and Hb < 10.6 g/dL was a good predictor for anemia at delivery (Hb < 10.5, Hb < 10 and Hb < 9.5 g/dL). Here, GSTM1 is linked to anemia (phenotype).