Occurrence of gestational diabetes mellitus and the value of different screening indicators for the oral glucose tolerance test

Background. The objective of the present study was to determine prevalence of gestational diabetes mellitus (GDM) in terms of impaired glucose tolerance (IGT) and diabetes mellitus (DM), and the value of traditional anamnestic risk factors for predicting outcome of the oral glucose tolerance test (OGTT). Methods. A prospective population-based study in a defined geographic area in Sweden. All pregnant nondiabetic women (n = 4918) attending maternal health care from July 1994 to June 1996 were offered a 75g OGTT in gestational weeks 28-32. Traditional anamnestic risk factors, as well as results of the OGTT in terms of fasting-B-glucose and 2h-B-glucose, were registered. Results. 3616 (73.5%) women agreed to perform the OGTT. Sixty-one (1.7%) of those had GDM [47 (1.3%) had impaired glucose tolerance and 14 (0.4%) had diabetes mellitus]. 15.8% fulfilled traditional risk factor criteria. Traditional anamnestic risk factors as an indicator to perform an OGTT identified 29/61 GDM women and 9/14 women with DM. Among primiparas, 4/21 with gestational diabetes mellitus were detected. Conclusion. Using traditional risk factors as an indicator to perform an OGTT gives a low sensitivity to detect GDM and even DM especially among primiparas.