The Clinical Significance of Abnormal 50 gm Oral Glucose Tolerance Test for Gestational Diabetes Screening

Lee, Jung Han; Hwang, Jeong Hye; Kim, Seung Ryong; Park, Moon Il; Chung, Sung Ro; Hwang, Yeon Young; Ahn, You Hern

Abstract

OBJECTIVE
The purpose of this study was to compare the clinical significance of pregnant women who had abnormal 50 g oral glucose tolerance test (GTT) but normal 100 g oral GTT with those who had normal 50 g oral GTT.
MATERIALS AND METHODS
Between March 1999 and Feb 2001, 812 pregnant women underwent 50 g oral GTT in the department of Ob/Gyn, Hanyang Univ. Hospital and these women were entered for this study. Among these women, those who showed abnormal 50 g oral GTT but normal 100 g oral GTT were entered for study group and those who showed normal 50 g oral GTT were entered for control group. For the perinatal outcome, average birth weight, frequency of macrosomia, intrauterine growth restriction (IUGR), premature birth, preeclampsia, cesarean section rate were compared for both groups.
RESULTS
Of 812 patients, 93 patients were entered for study group and 703 patients were entered for control group. The average birth weight of the fetus in the study group at 3359.3 grams was higher than the control group at 3243.6 grams (p<0.05). The frequency of macrosomia was 11.8% in the study group and 3.3% in the control group (p=0.0001). Premature birth occurred more frequently in the study group at 10.8% as compared to the control group at 4.8% (p<0.05). Other factors did not show any significant differences. But, although a higher rate of a macrosomia was seen in the study group than in the control group, the abnormal 50 g oral GTT was not risk factor after controlling for confounding risk factors by logistic regression modeling (OR 1.53). On the other hand, the maternal BMI and the increase in body weight during pregnancy were the risk factors of macrosomnia after controlling for confounding risk factors by logistic regression modeling (OR 6.27 and 5.58).
CONCLUSION
Abnormal 50 g oral GTT but normal 100 g oral GTT was not found to be a risk factor for macrosomia or pre-eclampsia. There needs to be personalized assessment of other risk factors in correlation with macrosomia, especially in obese women with a BMI greater than 26 before pregnancy, and in those with increase in body weight greater than 16 kg during pregnancy.