50 Grams Glucose Challenge Test for Screening of Gestational Diabetes Mellitus in Each Trimester in Potential Diabetic Pregnancy
Chanvitya Punthumapol MD*, Putthawan Tekasakul MD*
Affiliation : * Section of Obstetrics and Gynecology, Taksin Hospital, Bangkok
Objective : To evaluate the cutoff value of the 50 grams glucose challenge test (GCT) for screening of gestational
diabetes mellitus (GDM) in each trimester in potential diabetic pregnancy and to determine the prevalence of
GDM.
Study design: Retrospective descriptive study (Diagnostic test).
Results : Section of Obstetrics and Gynecology, Taksin Hospital.
Results : Two thousand and ten potential diabetic pregnant women who attended the antenatal care clinic at
Taksin Hospital between August 2004 and December 2005 were identified and recruited based on risk indicators.
Material and Method: A GCT was performed. If GCT was positive, 100 grams oral glucose tolerance test
(OGTT) was done to confirm the GDM. All relevant data including demographic information, GCT and OGTT
results were collected. The receiver operating characteristic (ROC) curve was used to identify the cutoff value
of GCT for screening of GDM.
Main outcome measures: The cutoff value of GCT for screening of GDM in each trimester by using ROC curve.
Results : The cutoff values of GCT in 1st, 2nd, 3rd, and all trimesters were 179, 177, 184, and 179 mg/dl respectively.
The authors recommended 177 mg/dl as the cutoff value of GCT for screening of GDM in potential diabetic
pregnancy in each trimester. The prevalence of GDM in 1st, 2nd, 3rd, and all trimesters were 14.22, 13.04, 11.96,
and 13.2% respectively.
Conclusion : The threshold of 177 mg/dl was recommended as the cutoff value of GCT for screening of GDM in
each trimester in potential diabetic pregnancy. The prevalence was 13.2%.
Keywords : 50 grams glucose challenge test, Gestational diabetes mellitus, Each trimester, Potential diabetic pregnancy
