Publication:

Evaluation of glucose challenge test using cut off values 130mg/dl and 140 mg/dl for gestational diabetes mellitus screening

Background Gestational Diabetes Mellitus (GDM) is associated with several adverse maternal and perinatal outcomes. Thus, screening for early detection of GDM and its treatment is important.

Methods This was hospital based descriptive study done over one year in department of Obstetrics and Gynecology, TUTH, Nepal. Six hundred ninety-seven women fulfilling the inclusion criteria were enrolled at 18-22 weeks of gestation. High risk factors were assessed and GCT was performed in women with risk factors during enrollment. Diagnostic OGTT was performed in women who screened positive (GCT ≥130mg/dl). Screen negative high-risk women were re-screened at 24-28 weeks. In women without known risk factors, GCT was performed at 24-28 weeks and OGTT was performed when screen positive. The diagnosis of GDM was made according to Carpenter and Coustan criteria.

Results Out of 697 enrolled women, 12 were excluded for various reasons and 685 women were analyzed. Women having risk of GDM were 28.9%. The prevalence of GDM was 2.92% and 2.48% with GCT cut off 130 mg/dl and 140 mg/dl respectively. Lowering the threshold to 130 mg/dl identified three extra cases (p=0.010). The prevalence among high risk group was 8.58% and 7.07% with the cut off value 130 mg/dl and 140 mg/dl respectively with three extra cases detected on taking cut off value 130 mg/dl (p=0.014). Among low risk women the prevalence of GDM was same i.e. 0.61% with both the cut off values.

Conclusions Lowering threshold of GCT to 130 mg/dl could identify significant percentage of extra cases of GDM especially in high risk women.