Metformin treatment for gestational diabetes

The prevalence of gestational diabetes mellitus (GDM) is rising as the pregnant population becomes older and more obese. This is concerning because GDM is associated with increased perinatal morbidity such as macrosomia and shoulder dystocia, and the need for instrumental delivery. In addition, the offspring of GDM women have increased long-term risks of obesity and type 2 diabetes. There is no doubt that treating women with GDM improves pregnancy outcomes. Conventionally this has been by diet and insulin. Although effective, insulin increases appetite leading to weight gain. It increases the risk of hypoglycaemia and needs to be given by injection. There is also a substantial cost in terms of time for teaching and educating patients. Metformin offers a logical alternative to insulin in GDM, by reducing insulin resistance. Recent trial evidence indicates it is safe and effective. We describe our experience with metformin in GDM and review the evidence.