GSTM1 and gestational diabetes: As shown in Table 5, after adjustment for potential confounders (maternal age, parity, history of GDM, family history of diabetes, pre-pregnancy BMI, ART pregnancy, chronic hypertension, smoking, early Hb and HbA1c), women with SF > 71.4 μg/L had a significantly increased risk of developing GDM compared to those with SF ≤ 71.4 μg/L (adjusted OR = 2.775; 95% CI: 1.191–6.466; p = 0.018).