Metformin therapy during pregnancy: good for the goose and good for the gosling too?
Type 2 diabetes and gestational diabetes mellitus (GDM) are closely related disorders characterized by increased insulin resistance. Metformin, a biguanide compound, exerts its clinical effect by both reducing hepatic glucose output and by increasing insulin sensitivity. This results in a decreased glucose level without an associated high risk of either hypoglycemia or weight gain. These characteristics have established metformin as an ideal first-line treatment for people with type 2 diabetes and, hypothetically, a particularly attractive drug for use in pregnancy. However, metformin is known to cross the placenta, and its use in pregnancy has been limited by concerns regarding potential adverse effects on both the mother and the fetus.