In our study, both fasting insulin and c-peptide levels were significantly decreased in GDM when compared with PRG, with the highest overall levels measured in the PRG group (Fig. 2b Insulin: PRG = 24.82 ± 4.09, GDM = 4.91 ± 1.65, PP = 5.03 ± 0.92, and NP = 2.64 ± 0.69 μU/mL; ANOVA p < 0.0001, PRG vs. GDM p < 0.001, PRG vs. PP p < 0.001, PRG vs. NP p < 0.001. Here, INS is linked to gestational diabetes.