One Versus Two Abnormal Glucose Values in 100-g, 3-Hour Oral Glucose Tolerance Test during Pregnancy and Risk of Adverse Pregnancy Outcomes

Introduction: To study the incidence, risk factors, and pregnancy outcomes associated with gestational diabetes mellitus (GDM) diagnosed with Carpenter and Coustan (C&C) criteria and new approach of American College of Obstetrician and Gynecologists (ACOG).Materials & Methods: 836 pregnant women free from GDM or overt diabetes were screened at 24-28 weeks using the 50-g glucose challenge test followed by 100-g, 3-hour oral glucose tolerance test (OGTT). GDM was determined if the criteria of C&C or new approach of ACOG were met. Results: GDM incidence was 4.2% (95% CI: 2.9-5.5) using C&C criteria and increased by 33.3% using new approach of ACOG (5.6%, 95% CI: 4.0-7.2). Previous cesarean section and family history of diabetes significantly increased the risk of developing GDM using both criteria. Older age, higher pre-pregnancy BMI, and physical inactivity also increased significantly the risk of developing GDM using C&C criteria. GDM was an independent predictor of macrosomia, cesarean section, and large for gestational age when using both criteria, the associations were stronger when using C&C criteria. Conclusion: Although both C&C criteria and new approach of ACOG may have similar diagnostic efficacy, using C&C diagnostic criteria is more sensitive than new approach of ACOG for diagnosis of GDM.