INS and Obesity: In the multiple logistic regression analysis, we identified that maternal age at delivery ≥35 years, overweight, and obesity elevated the risk of developing GDM during twin pregnancies (OR = 1.307, 95% CI = 1.055–1.618, P = 0.014; OR = 1.611, 95% CI = 1.315–1.973, P < 0.001; OR = 2.951, 95% CI = 1.828–4.762, P < 0.001, respectively), and the proportion requiring insulin therapy (OR = 1.881, 95% CI = 1.073–3.295, P = 0.027; OR = 2.450, 95% CI = 1.422–4.223, P < 0.001; OR = 4.056, 95% CI = 1.728–9.522, P < 0.001, respectively) (Table 2).