INS and gestational diabetes: A proof-of-concept study in forty women with prior GDM showed that a 16-weeks treatment with metformin and sitagliptin significantly increased first-phase insulin secretion from 720.3 ± 299.0 to 995.5 ± 370.3 pmol/L (P = 0.02) but no significant change was observed with sitagliptin or metformin alone (111).