Intensive Management of Gestational Diabetes
Does intensive management of gestational diabetes improve outcomes?
There is not enough evidence to support dietary or drug treatment in patients with gestational diabetes.
Gestational diabetes and impaired glucose tolerance are associated with macrosomia and may be associated with increased risk for cesarean delivery, shoulder dystocia, and birth trauma. Although preexisting diabetes has been shown to increase the risk of poor perinatal outcomes, it is not clear that data relating to preexisting diabetes can be extrapolated to patients with gestational diabetes.
Tuffnell and colleagues searched the Cochrane Pregnancy and Childbirth Group trials register, the Cochrane Central Register of Controlled Trials, and bibliographies of relevant articles. They identified three studies of 223 women with impaired glucose tolerance; none of these studies was a randomized controlled trial comparing management strategies. Treatment of women with impaired glucose tolerance did not offer a statistically significant benefit over nontreatment in terms of abdominal operative delivery rates, neonatal intensive care admissions, or reduction in birth weight. Treatment may be associated with a reduced incidence of neonatal hypoglycemia. The trials had wide confidence intervals and methodologic shortcomings. The small number of patients studied meant that a small but clinically meaningful benefit may have been missed.
In the face of limited and inconsistent research, the American College of Obstetricians and Gynecologists (ACOG) continues to recommend universal screening for gestational diabetes.1 It recommends that insulin therapy be considered in patients for whom nutritional therapy does not result in a fasting glucose level of less than 95 mg per dL (5.3 mmol per L), a one–hour post-prandial glucose level of less than 130 to 140 mg per dL (7.2 to 7.8 mmol per L), or a two-hour postprandial glucose level of less than 120 mg per dL (6.7 mmol per L). ACOG also recommends that physicians consider elective cesarean delivery for women with gestational diabetes and an estimated fetal weight greater than 4,500 g (9 lb, 15 oz). ACOG does not make a recommendation for or against calorie restriction in obese women with gestational diabetes.
Intensive management of gestational diabetes is time-consuming and resource-intensive. Overall, evidence is insufficient to support therapy for gestational diabetes. However, universal screening is the standard of care in most communities. When faced with abnormal results, most family physicians will opt to follow the consensus opinion of our specialist colleagues.