To date, several studies have shown that metformin therapy has greater benefits compared with insulin and glibenclamide as GDM treatments, such as lower risk of large for gestational age babies or macrosomia, neonatal hypoglycemia, and admission to neonatal intensive care units (Rowan et al., 2008; Butalia et al., 2017; Farrar et al., 2017). This evidence concerns the gene INS and gestational diabetes.