Objective: To assess the prevalence of GDM in pregnant women aged 30 to 34 years old who were screened by glucose challenge test (GCT) at Phramongkutklao Hospital
Material and Method: The cross-sectional data were collected from 1332 pregnant women aged between 30-34 years who attended the antenatal care clinic and delivered at Phramongkutklao Hospital from March, 2003 to January, 2005. The 564 pregnant women aged between 30-34 years old who joined the project were tested by GCT at the gestational age of 24-28 weeks. If the level of blood sugar was the abnormal results, 100-g, 3-hour oral glucose tolerance test (OGTT) would be conducted. All relevant data including demographic information, risks factor for GDM, GCT and OGTT results and pregnancy outcomes were collected for further statistical analysis.
Results: There were 1332 pregnancies enrolled into the study. The 564 pregnant women were eligible for GCT with 228 positive results. Thirty-two cases of GDM were detected with the prevalence of 5.7%. In the GDM group, percentage of the common risk factors were family DM (28.1%) glucosuria (12.5%). Furthermore, only one case of premature rupture of membrane and one case of pregnancy-induced hypertension were found. Preterm labor, LGA, SGA, birth asphyxia, fetal anomalies and cesarean section were observe in 3.1%,9.4%,0%, 0%, 0%, and 40.6% respectively
Conclusion: The prevalence rate of GDM in pregnant women aged 30-34 years old screened by GCT at Phramongkutklao Hospital is 5.7%. The GDM class A1 were 23 cases (4.1%) and GDM class A2 were nine cases (1.6%). Their impact on obstetric complication and pregnancy outcome was inconclusive due to the small number of cases.

Keywords: GDM, Age, Prevalence of GDM, GCT, OGTT