A diagnostic strategy for gestational diabetes mellitus: Clinical and metabolic results

Objective: Perinatal morbidity and mortality are increased in pregnancies c omplicated by untreated or undetected gestational diabetes mellitus (GDM), but there is little agreement on how to screen for or diagnose the conditio n. We evaluated a sensitive diagnostic strategy for GDM. Methods: We conducted an oral glucose tolerance test (oGTT) with 75 g of gl ucose in 1621 unselected pregnant women between 24 and 28 weeks' gestation. Patients with a positive screening test underwent a second, diagnostic oGT T. A diagnosis of GDM was made if serum glucose exceeded one of the followi ng limits: 100 mg/dL at fasting, 160 mg/dL at 1 hour, 140 mg/dL at 2 hours, and 120 mg/dL at 3 hours. Results: A total of 97 of the 1621 (6.0%) women met the diagnosis of GDM, 6 1 had impaired glucose tolerance (positive screening test but negative diag nostic test). Women with intermediate glucose tolerance were similar in age and BMI to 104 women with normal glucose tolerance and had serum glucose a nd insulin levels during oGTT between those of women with GDM and women wit h normal glucose tolerance. The neonatal outcome in women with (treated) GD M was similar to that in women with normal glucose tolerance, whereas in (u ntreated) women with IGT birth weight and the rate of macrosomia tended to be higher. Conclusion: Our data support the concept of a continuum of glucose toleranc e during pregnancy. A diagnostic strategy aiming at detecting even minor al terations of glucose tolerance ("mild" GDM) yielded good neonatal results a nd appears to be clinically useful.