Management of gestational diabetes mellitus.

Gestational diabetes mellitus is a common but controversial disorder. While no large randomized controlled trials show that screening for and treating gestational diabetes affect perinatal outcomes, multiple studies have documented an increase in adverse pregnancy outcomes in patients with the disorder. Data on perinatal mortality, however, are inconsistent. In some prospective studies, treatment of gestational diabetes has resulted in a decrease in shoulder dystocia (a frequently discussed perinatal outcome), but cesarean delivery has not been shown to reduce perinatal morbidity. Patients diagnosed with gestational diabetes should monitor their blood glucose levels, exercise, and undergo nutrition counseling for the purpose of maintaining normoglycemia. The commonly accepted treatment goal is to maintain a fasting capillary blood glucose level of less than 95 to 105 mg per dL (5.3 to 5.8 mmol per L); the ambiguity (i.e., the range) is due to imperfect data. The postprandial treatment goal should be a capillary blood glucose level of less than 140 mg per dL (7.8 mmol per L) at one hour and less than 120 mg per dL (6.7 mmol per L) at two hours. Patients not meeting these goals with dietary changes alone should begin insulin therapy. In patients with well-controlled diabetes, there is no need to pursue delivery before 40 weeks of gestation. In patients who require insulin or have other comorbid conditions, it is appropriate to begin antenatal screening with nonstress tests and an amniotic fluid index at 32 weeks of gestation.