INS and gestational diabetes: In conclusion, this small feasibility study shows that a large randomised controlled trial comparing additional glibenclamide or insulin in women with GDM who are failing to achieve adequate glycaemic control with metformin alone is feasible, but is unlikely to be clinically worthwhile given both the poorer glycaemic control with glibenclamide and metformin in this pilot study and the lack of universal preference for glibenclamide over insulin.