Assessment of the appropriate cut-off point in glucose challenge test based on the risk of gestational diabetes in pregnant women

Document Type : Original Article


1 Associate Professor, Department of Obstetrics and Gynecology, School of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.

2 Professor, Department of Social Medicine and Work Environment Research Center, School of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran

3 General Practitioner, School of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran

4 MSc of Epidemiology, School of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran


Introduction: Determination of the appropriate basis in glucose challenge test is considered as the most important problems discussed in screening for Gestational Diabetes Mellitus. Therefore, this study was conducted with aim to assess the appropriate cut-off point in glucose challenge test in pregnant women.
Methods: In this study, data of Iranian pregnant women without diabetes referring to Rafsanjan gynecology clinics for assessment of gestational diabetes were collected. GCT was performed for the women in 24 to 28 weeks of pregnancy. Oral Glucose Tolerance Test was performed for women who their test result was ≥135 mg/dl and ≤200 mg/dl. The OGTT results were interpreted by Carpenter and Coustan criteria. Finally, the appropriate cut-off point of GCT was calculated by SPSS software (version 22) and the ROC curve.
Results: The results of GCT showed that the maximum and minimum values of GCT were 93 and 199 mg/dl respectively, with mean±SD of 161.99±15.83 mg/dl. 235 cases of pregnant women had positive GTT test. According to the ROC curves for all study population, GTT cut-off point was 140 mg/dl with 97% sensitivity, in low-risk group for gestational diabetes was 147 mg/dl with 96% sensitivity and for high risk group was 135 mg/dl with 100% sensitivity and had the most predictive value.
Conclusion: Suitable cut-off point in GCT for gestational diabetes is different in low and high risk pregnant women. Depending on the presence or absence of risk factors in mothers, we can reduce or increase the cut-off point of the GCT.


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