International Association of Diabetes and Pregnancy Study Groups Recommendations on the Diagnosis and Classification of Hyperglycemia in Pregnancy

The International Association of Diabetes and Pregnancy Study Groups (IADPSG) was formed in 1998 as an umbrella organization to facilitate collaboration between the various regional and national groups that have a primary or significant focus on diabetes and pregnancy. The principal objectives of IADPSG are to foster an international approach to enhancing the quality of care, facilitating research, and advancing education in the field of diabetes in pregnancy. During 11–12 June 2008, the IADPSG sponsored an International WorkshopConference on Gestational Diabetes Diagnosis and Classification in Pasadena, California. More than 225 conferees from 40 countries reviewed published results of the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study, additional unpublished HAPO study findings, and results of other work that examined associations of maternal glycemia with perinatal and long-term outcomes in offspring. Conferees then held regional caucuses to consider clinical implications of the information that had been presented. On 13 June 2008, the IADPSG Consensus Panel (with representation from the 10 member organizations of the IADPSG and other organizations with an interest in diabetes and pregnancy) was convened. Members of the IADPSG Consensus Panel are listed in the online-only appendix, available at http://care.diabetesjournals. org/cgi/content/full/dc09-1848/DC1. Subsequently, the IADPSG Consensus Panel reviewed further HAPO study results. Through this process, the consensus summarized in this report was reached. This report represents the opinions of individual members of the IADPSG Consensus Panel and does not necessarily reflect the position of the organizations they represent. It is expected that this report will be considered by diabetes, obstetric, and other organizations and will serve as the basis for internationally endorsed criteria for the diagnosis and classification of diabetes in pregnancy. Gestational diabetes mellitus (GDM), a common medical complication of pregnancy, is defined as “any degree of glucose intolerance with onset or first recognition during pregnancy” (1,2). The initial criteria for its diagnosis were established more than 40 years ago (3) and, with modifications (4), remain in use today. These criteria were chosen to identify women at high risk for development of diabetes after pregnancy (5) or were derived from criteria used for nonpregnant individuals (6) and not necessarily to identify pregnancies with increased risk for adverse perinatal outcome. There is consensus that overt diabetes during pregnancy, whether symptomatic or not, is associated with significant risk of adverse perinatal outcome. The risk of adverse perinatal outcome associated with degrees of hyperglycemia less severe than overt diabetes is controversial. Several factors contribute to this longstanding controversy. Some have attributed risks of adverse outcomes associated with GDM, such as birth weight that is large for gestational age (LGA), excess fetal adiposity, and higher rate of cesarean section, to confounding characteristics, such as obesity, more advanced maternal age, or other medical complications, rather than glucose intolerance (7–9). Bias of caregivers toward expectation of adverse outcomes may increase morbidity due to increased intervention (10). Some suggest that criteria currently in wide use for the diagnosis of GDM are too restrictive and that lesser degrees of hyperglycemia increase risk of adverse perinatal outcomes (11– 16). Conversely, others believe that systematic efforts to identify GDM should be stopped unless data become available to link significant morbidities to specific degrees of glucose intolerance (8). Lack of international uniformity in the approach to ascertainment and diagnosis of GDM has been a major hurdle (2). Questions have been raised regarding cost-effectiveness and benefit of detecting and treating GDM. Recent recommendations of the U.S. Preventive Services Task Force, the U.K. National Health Service, and the Canadian Task Force on the Periodic Health Examination assert that there is not sufficient high-level evidence to make a recommendation for, or against, screening for GDM (17–19). Recently, a cost-effectiveness study undertaken by the U.K. National Institute for Health and Clinical Excellence concluded that “screening, diagnosis, and treatment of gestational diabetes is cost-effective” (20). As currently defined (1,2), GDM includes a subgroup with more severe hyperglycemia (similar to that seen in preexisting diabetes) that presents special issues concerning management during pregnancy and postpartum follow-up. The issues raised by inclusion of this subgroup with those with GDM are of greater concern because of the rising prevalence of obesity, type 2 diabetes, and other met● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●