The mean fasting glucose (105.6 ± 7.4 vs. 70.2 ± 7.2 mg/dL, p < 0.001), glycated hemoglobin (HbA1c) (5.6 ± 0.5 vs. 4.9 ± 0.5%, p < 0.001), insulin (11.1 (6.8) vs. 8.7 (2.6) μIU/mL, p = 0.006), and HOMA-IR (3.0 (1.8) vs. 1.4 (0.6), p < 0.001) levels were significantly higher in women with GDM than in controls. This evidence concerns the gene INS and gestational diabetes.