In the United States, use of oral hypoglycemic agents is controversial and not approved by the US Food and Drug Administration. That said, many practices have successfully used glyburide to manage GDM when diet alone was insufficient, although a significant number of these patients go on to require insulin in order to maintain optimal glycemic control. Another oral hypoglycemic agent that is being considered as a substitute to insulin is metformin. Rowan and colleagues compared the use of metformin and insulin in women diagnosed with GDM. Of note, neonatal complications did not vary between the 2 subject groups. There was less severe hypoglycemia in the infants of mothers on metformin. Preterm birth was more common in the metformin group, but there was no increase in other complications. Women who used metformin were more likely to say they would use metformin in a subsequent pregnancy (76%) than were women on insulin (27.2%). Among the women on metformin, 46.3% had to be on supplemental insulin as well. The overall conclusion of this study was that metformin was a safe option for GDM, and it was more agreeable to the patient. There have not been any trials comparing glyburide and metformin.