Prevalence of Gestational Diabetes Mellitus (GDM) in Women Screened by Glucose Challenge Test (GCT) at Maharaj Nakorn Chiang Mai Hospital
Pharuhas Chanprapaph MD*,
Affiliation : Chatdao Sutjarit MD*
* Department of Obstetrics and Gynecology, Faculty of Medicine, Chiang Mai University
Objective : To assess the prevalence of GDM in GCT screened women at Maharaj Nakorn Chiang Mai
Hospital.
Study
Design : Retrospective descriptive study.
Setting : Department of Obstetric and Gynecology, Maharaj Nakorn Chiang Mai Hospital.
Materials and Methods : One thousand pregnant women who attended the antenatal care clinic and delivered
at Maharaj Nakorn Chiang Mai Hospital from October 2001 to December 2002 were recruited into the study.
Glucose challenge test (GCT), 50-g glucose oral load with 1-hr plasma glucose measurement, was performed
in GDM high-risk pregnancies. If GCT was positive, oral glucose tolerance test (OGTT), 100-g glucose
orally, was done to confirm the final diagnosis. All relevant data including demographic information, previous
obstetric history, risk factors for GDM, GCT and OGTT results and pregnancy outcomes were collected for
further statistical analysis.
Main Outcome Measures : Prevalence of GDM in GCT screened women, obstetric complications and pregnancy
outcomes.
Results : There were totally 1,000 pregnancies enrolled into the study. Despite 451 pregnant women being
eligible for GCT, only 411 cases were tested with 164 positive results. 29 cases of GDM were detected with the
prevalence of 7.05%. (CI 95% = 0.048, 0.099). As a result, the sensitivity, specificity, positive predictive
value, and negative predictive value of GCT were 100%, 64.66%, 17.68% and 0%, respectively. In the GDM
group, the common indications for GCT screening were advanced maternal age (75.4%), familial diabetic
history (22.1%) and glycosuria (6.8%). Furthermore, only 1 case of pregnancy-induced hypertension was
found with cesarean section, preterm birth, LGA and SGA of 27.6%, 10.3%, 3.45% and 13.79%, respectively.
There were 2 cases of pregestational diabetes mellitus (PGD; 0.2%) with 40 high-risk pregnancies (4%)
without screening.
Conclusion : The selective GCT screening strategy was highly effective and revealed 7.05% of GDM prevalence.
Its impact on obstetric complication and pregnancy outcome was inconclusive due to the small number of
studied population. Careful history reviewing plays an important role in identifying GDM risk factor for
GCT screening.
Keywords : Gestational diabetes mellitus (GDM), Prevalence of GDM, Glucose challenge test (GCT), Oral glucose tolerance test (OGTT), Selective screening strategy
