Incidence of Gestational Diabetes Mellitus among Pregnant Women with One Abnormal Value of Oral Glucose Tolerance Test
Sornlada Thanasuan MD*, Dittakarn Borriboonhirunsarn MD, MPH, PhD*
Affiliation : * Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital, Mahidol University
Objective : To compare the incidence of Gestational Diabetes Mellitus (GDM) between pregnant women
with one abnormal value of oral glucose tolerance test (Study group) and those with normal screening test
(Control group) and compare their pregnancy outcomes.
Design : Retrospective cohort study.
Setting : Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital.
Materials and Methods : Two hundred and twenty eight at-risk pregnant women were enrolled from January
2003 to November 2004. They were divided equally with 114 each in study and control group. All received
GDM screening before 24 weeks of gestation following the guidelines used at Siriraj Hospital. Data collection
included baseline characteristics, data on clinical risks and screening results, final diagnosis, maternal and
neonatal complications. Incidence of GDM and pregnancy outcomes was compared between the two groups.
Results : Both groups’ baseline characteristics and clinical risks were comparable, except that the mean age
of women in the study group was significantly greater than in the control group (32.8 + 4.9 and 29.7 + 5.5
years, p < 0001). The incidence of GDM was significantly higher among in study group compared with the
control group (21.9% and 1.8% respectively, RR 12.5, 95%CI 3.0-51.5). After adjusting for maternal age,
abnormal one OGTT value was the only independent risk for developing GDM (adjusted OR 16.3, 95%CI 3.7-
71.9, p < 0.001). Infants of the study group had significantly higher birth weight than those of the control
group (3203.6 + 563.9 and 3050.7 + 457.8 g respectively, p = 0.026). Rate of primary cesarean section,
asphyxia, macrosomia, low birth weight, and other neonatal complications were comparable between the two
groups.
Conclusion : Pregnant women with one abnormal value of oral glucose tolerance test had a significantly
greater risk of developing GDM compared to women with normal screening test. Pregnancy outcomes between
the two groups were not significantly different.
Keywords : Gestational diabetes mellitus, Incidence, One abnormal value, Oral glucose tolerance test
