INS and preeclampsia: Compared with metformin, insulin had a significant increase in the risk of preeclampsia (RR, 0.57; 95% CI, 0.45 to 0.72; P < 0.001), NICU admission (RR, 0.75; 95% CI, 0.64 to 0.87; P < 0.001), neonatal hypoglycemia (RR, 0.57; 95% CI, 0.49 to 0.66; P < 0.001), and macrosomia (RR, 0.68; 95% CI, 0.55 to 0.86; P < 0.05).