The treatment of gestational diabetes comprise of:
Gestational diabetes is deﬁned as "glucose intolerance ﬁrst detected during pregnancy which returns to normal following termination of pregnancy". It is associated with 2 to 3-fold increase in perinatal  mortality. It is frequently associated with macrosomia, stillbirth and polyhydramnios. To restrict the plasma glucose levels around 100 mg % insulin may be required. 
Sulfonylureas cross the placental  barrier and are likely to exert their action on fetal pancreas.
It is better to use human insulin or monocomponent puriﬁed insulins, as they are less antigenic.
Glibenclamide
Chlorpropamide
Glipizide
Insulin