gestational diabetes mellitus (GDM), a disorder characterized by an impaired ability to metabolize carbohydrates, usually caused by a deficiency of insulin or insulin resistance, occurring in pregnancy. It disappears after delivery of the infant but in a significant number of cases returns years later as type 2 diabetes mellitus. Evidence suggests that placental lactogen and considerable destruction of insulin by the placenta play a role in precipitating GDM. Treatment consists of self-monitoring of blood glucose, insulin administration, increased activity, a meal plan that controls the amount of carbohydrates eaten, and an adequate intake of calcium and iron. See also diabetes mellitus.
