Carpenter-Coustan Criteria Compared With the National Diabetes Data Group Thresholds for Gestational Diabetes Mellitus

OBJECTIVE: To examine perinatal outcomes in women who would meet the diagnostic criteria for gestational diabetes mellitus (GDM) according to the Carpenter and Coustan but not by the National Diabetes Data Group (NDDG) thresholds. METHODS: This is a retrospective cohort study of women screened for GDM between January 1988 and December 2001. During the study period, only women who were diagnosed with GDM by the NDDG criteria received counseling and treatment. Women diagnosed with GDM according to the Carpenter and Coustan thresholds but not by the NDDG criteria were compared with women without GDM by either criteria. Perinatal outcomes were examined using V test and multivariable logistic regression analyses. RESULTS: Among the 14,693 women screened for GDM, 753 (5.1%) would have GDM diagnosed by the Carpenter and Coustan criteria and 480 (3.3%) by the NDDG criteria only, giving 273 (1.9%) women as the study group. Compared with women without GDM, women with GDM by the Carpenter and Coustan but not by the NDDG criteria had higher odds of cesarean delivery (OR 1.44, 95% confidence interval [CI] 1.01-2.07), operative vaginal delivery (OR 1.72, 95% Cl 1.20-2.46), birth weight greater than 4,500 g (OR 4.47, 95% CI 2.26-8.86), and shoulder dystocia (OR 2.24, 95% Cl 1.03-4.88). CONCLUSION: Women diagnosed with GDM by the Carpenter and Coustan criteria but not by the NDDG criteria had higher risk of operative deliveries, macrosomia, and shoulder dystocia. We recommend using the Carpenter and Coustan diagnostic thresholds for GDM, because these diagnostic criteria are more sensitive than the NDDG criteria. (Obstet Gynecol 2009;114:326-32)