After adjusting for confounders, the ORs comparing the high ranges with the reference range of Hb both demonstrated significantly increased odds of GDM (OR: 1.27 for 130 g/L ≤ Hb < 150 g/L; OR: 2.06 for Hb ≥ 150 g/L) and PE (OR: 1.30 for 130 g/L ≤ Hb < 150 g/L; OR: 2.38 for Hb ≥ 150 g/L). Here, GSTM1 is linked to gestational diabetes.