INTRODUCTION-The Fourth International Workshop-Conference on Gestational Diabetes Mellitus (GDM) was convened in Chicago, Illinois, on 14 March 1997, under the sponsorship of the American Diabetes Association. The meeting provided a forum for review of new information concerning GDM in the areas of diagnosis and prevalence, perinatal and long-range implications for the mother and her offspring, and management strategies. There is a general consensus that the prevalence of GDM is increasing globally, but there is considerable controversy about the clinical importance of GDM and the magnitude of its impact on mother and offspring. Lack of uniformity in approach to detection and diagnosis of GDM has hampered efforts to resolve these issues. The Summary and Recommendations of the Third International Workshop-Conference on Gestational Diabetes Mellitus emphasized the critical importance of developing new diagnostic criteria that are based on the potential to detect pregnancies at risk for adverse perinatal outcome as a result of maternal hyperglycemia, rather than placing primary emphasis on the identification of mothers at risk for progression to diabetes outside of pregnancy, This objective has not yet been fulfilled; however, efforts are being made to address this via a multicenter study Conference participants reviewed data indicating that degrees of glucose intolerance less severe than the currently recommended National Diabetes Data Group (NDDG) criteria for GDM (1) may be associated with an increased risk of adverse perinatal outcome. Extrapolation from the whole blood glucose values found by O'Sullivan and Mahan (2) to plasma or serum glucose concentrations to take into account the specific enzymatic methods currently in use, as proposed by Carpenter and Coustan (3), yields lower values for abnormal plasma glucose concentrations and increases the number of pregnancies defined as GDM. Additional studies have been performed, using approaches similar to that of O'Sullivan in his original study, to define abnormal 75-g oral glucose tolerance test (OGTT) values in different populations. This approach has yielded values for plasma glucose concentrations that are similar to the Carpenter/Coustan extrapolations of the 100-g OGTT. The conference participants concluded that the use of either a 100-g or a 75-g diagnostic test is acceptable, pending the development of criteria specifically relating glycemia to adverse pregnancy outcome.

Reports indicate that when GDM is diagnosed and treated intensively, the risk of intrauterine fetal death is not greater than that of the general obstetric population, and the overall frequency and severity of perinatal morbidities are less when GDM is managed intensively than when GDM is not managed intensively Fetal size in excess of that expected for gestational age, primarily resulting from an increase in adipose tissue mass, remains the greatest source of perinatal morbidity in GDM, in particular leading to higher rates of cesarean delivery and birth trauma. There is a need for more accurate estimation of the fetus at risk for birth trauma. Wellstandardized neonatal anthropometry can provide a good indication of body composition of the newborn infant.