In the second half of pregnancy, Hb levels were significantly reduced (115 vs. 120 g/L, P = 0.048) and the prevalence of anemia was increased (OR = 6.384, 95%CI: 2.498–16.311) in the hypothyroid pregnant women after adjusted for TPOAb, maternal age, body mass index (BMI),nulliparity, smoking and drinking (Tables 3, 4). Here, GSTM1 is linked to anemia (phenotype).