Predictive Value of 1 Hour 50g Oral Glucose Load Screening Test for Gestational Diabetes Mellitus Compared to 3 Hour Oral Glucose Tolerance Test in High Risk Pregnant Women

Abstract

A prospective study for detecting gestational diabetes mellitus was undertaken to evaluate the use of one hour plasma glucose level after 50 g glucose loading test (1‐hr GLT) as compared to the traditional 3‐hours 100 g oral glucose tolerance test (3‐hr OGTT) in 396 high risk cases. Each patient, had 1‐hr GLT and 3‐hr OGTT performed in a separate week. Forty‐two cases (10.6%) who had abnormal 3‐hr OGTT were classified as gestational diabetes (GDM). One hundred and sixty cases (40.4%) had an abnormal 1‐hr GLT (plasma glucose level ≥140 mg/dl). Thirty‐six of these 160 cases (22.5%) had an abnormal 3‐hr OGTT. In 236 women (59.6%) that had normal 1‐hr GLT (plasma glucose level <140 mg/dl) only 6 cases (2.5%) had an abnormal 3‐hr OGTT. If 1‐hr plasma glucose level ≥150 mg/dl was used as the cutoff point, 110 cases (27.8%) were found to have abnormal 1‐hr GLT, and 35 of these 110 cases (31.8%) had an abnormal 3‐hr OGTT. Seven of 286 women (2.4%) that had normal 1‐hr GLT (plasma glucose level <150 mg/dl) had an abnormal 3‐hr OGTT. The sensitivity and specificity of the 1‐hr GLT when abnormal 3‐hr OGTT was used as gold standard for detecting GDM were 85.7% and 65% respectively (BS ≥140 mg/dl). Whereas the sensitivity and specificity were 83.3% and 78.8% respectively when plasma glucose level >150 mg/dl was used as the cut point. From this study in oriental pregnant women it can be concluded that 1‐hr GLT is a valuable screening test for GDM. © 1993 Japanese Society of Obstetrics and Gynaecology