Gestational Diabetes Mellitus Screening In Twin Pregnancies

The purpose of this study was to ideal cutoff in plasma glucose levels in screening for gestational diabetes mellitus (GDM) in twin pregnancies. A total 311 twin pregnancies were identified from hospital data base from 2007 to 2015. A 50 gram oral glucose challenge test (GCT) was performed at 24–28 weeks’ gestation. In those with a GCT of≥130 mg/dL underwent a 100-gram threehour oral glucose tolerance test (OGTT). The diagnosis of GDM was made if two of the four values on the oral glucose tolerance test were abnormal (The Carpenterand Coustanvalues). The screening results of the GCT was evaluated with ROC curve analysis to obtain a complete sensitivity/specificity at different cut-off points. We excluded all patients with pre-gestational diabetes and GDM diagnosed before 24 weeks of gestation. The positive screen rate was 32.5%. The incidence of GDM was 7.1%. The ROC analysis showed that a GCT cutoff of >135 mg/dL maintained 100% sensitivity, with a specificity of 78.2%. The positive predictive value was 22.9% and the negative predictive value was 100%. Area under ROC curve (AUC) was 0.948. Compared to a cutoff of ≥130 mg/dL, a cutoff of >135 mg/dL resulted in 5.1% less patients testing positive while maintaining the same 100% sensitivity. In twin pregnancy screening, a 50 gram GCT cutoff appears to be 135 mg/dL.