Glucose tolerance test during pregnancy: The significance of one abnormal value

Abstract

To determine the perinatal impacts of one abnormal oral glucose tolerance test (GTT) value, we conducted a retrospective study of pregnancy outcome in our population. Pregnant women (4314) were screened for gestational diabetes (GDM) between 24 and 32 weeks with the 50-g glucose challenge test and 183 were directly tested with the 100-g GTT. The subjects who had a serum glucose value equal or greater than 7.8 mmol/L 1 h after a 50-g glucose challenge were scheduled for a 100-g GTT (904). Another 32 subjects, who were not screened, were found to have gestational diabetes identified by repeated fasting and postprandial serum glucose measurements. Retrospectively, the study population was divided in four groups: I, normal (4138); II, GDM (237); III, subjects with one abnormal GTT value treated like GDM (85); IV, subjects with one abnormal GTT value untreated (69). Patient characteristics of groups II, III, and IV were similar. The area under the glycemic curve was similar between groups III and IV and was statistically inferior to that of Group II. GTT periodicity was the greatest in group II. Group II showed a higher rate of delivery before 37 weeks, of chronic and pregnancy induced hypertension, and of cesarian section but groups III and IV were not statistically different from group I. Percentages of macrosomic infants were comparable for the four groups; incidence of neonatal hypoglycemia was similar in groups I, III, and IV and it was significantly increased in group II (21%); other parameters such as icterus, respiratory distress syndrome, tachypnea, fractures, or death were not statistically different between the groups except for hypocalcemia that was increased in group II ( p < 0.01). These results lead us to conclude that in our population of pregnant women who had ready access to a pregnancy follow-up program, one abnormal GTT value has no measurable negative impacts on perinatal outcome and therefore does not necessitate specific treatment different from that of normal subjects.