On the other hand, high Hb concentrations were associated with increased odds of gestational diabetes (≥120 g/L OR (95% CI); 1.93 (1.33−2.81); ≥130 g/L; 1.71 (1.19−2.46); ≥140 g/L; 2.10 (1.65−2.68)). Here, GSTM1 is linked to gestational diabetes.