Objective: This is a retrospective study that is designed to investigate the prognosis of the patients with abnormal diabetes screening test and a negative 100 g oral glucose tolerance test that is accepted as the diagnostic test for gestational diabetes mellitus (GDM).
Materials and method: The records of 281 pregnant patients were reviewed. The data of the patients divided into groups with normal diabetes screening (1 h/50 g oral glucose tolerance test) and abnormal diabetes screening. The patients with abnormal diabetes screening were further divided into all values normal in 100 g Oral glucose tolerance test (OGTT), one value abnormal in 100 g OGTT and GDM subgroups. The prognosis of these patients was reanalyzed concerning the complications that may be attributed to glucose intolerance.
Results: Abnormal diabetes screening test was detected in 89 patients (31.6%) and 14 cases were diagnosed as GDM (4.9%). The data of 9 patients were not suitable to analyze. In 31 cases out of 80 (38.75%), an obstetric complication was detected. The rate of similar complications was 27.0% (52/192) in the control group. The difference in the rate of complications was not statistically significant (p>0.05). When the patients with one value abnormal in 100 g OGTT, were further evaluated, the complication rates were 3/9 (33.3%) for the 1st hour abnormal patients, 1/1 for the 2nd hour abnormal patients and 1/1 for the 3rd hour abnormal patients. When the values of 100 g OGTT were compared in complicated and uncomplicated cases, the difference between the groups was not statistically significant (p>0.05).
Conclusion: 100 g OGTT is the universal diagnostic test for GDM. There is a major subgroup of patients whose screening positive but diagnostic test (100 g OGTT) negative. These patients seem to be prone to develop obstetric complications related to glucose intolerance but there is not a proper means to detect these patients in clinical practice.