50-grams glucose challenge test for screening of gestational diabetes mellitus in high risk pregnancy.

OBJECTIVE

To evaluate the cutoff value of the 1-hr, 50-gram glucose challenge test (GCT) for screening of gestational diabetes mellitus (GDM), in high-risk pregnancy, and to determine the prevalence of GDM in this group.

STUDY DESIGN

Descriptive study (Diagnostic test).

SUBJECTS

Eight hundred and thirty-eight pregnant women, 24-28 weeks, were identified and recruited based on risk indicators between January and October 2004.

MATERIAL AND METHOD

A GCT was performed in this group. All women with plasma glucose value > or = 130 mg/ dl were given a 3-hr, 100-gram glucose tolerance test (OGTT) to diagnose gestational diabetes mellitus using Carpenter and Coustan diagnostic criteria. The receiver-operator characteristic (ROC) curve was used to identify the cut-off value of GCTfor detecting GDM.

MAIN OUTCOME MEASURES

The cut-off value of GCTfor detecting GDM by using ROC curve with the sensitivity and specificity of various cut-off values.

RESULTS

The ROC curve identified a GCT value of > or = 140 mg/dl as the cut-off value for detecting GDM, which showed the sensitivity and specificity of 95.3% and 48.6% respectively. The prevalence of GDM in high-risk pregnant women was 20.17% (169/838).

CONCLUSIONS

Recommended threshold of 140 mg/dl used as the cut-off value of 50-gram, 1-hr GCTfor screening GDM in high-risk pregnancy.