Changing diagnostic criteria for gestational diabetes: are implications the same for every country?

Evidence in support of the International Association of Diabetes in Pregnancy study groups' criteria for diagnosing gestational diabetes mellitus worldwide in 2019

Gestational diabetes mellitus, the most frequent medical complication of pregnancy, affects 5-6% of women in the United States with the use of the currently predominant Carpenter-Coustan criteria, which still represent the preferred approach of the American College of Obstetricians and Gynecologists. Alternative criteria proposed by the International Association of Diabetes in Pregnancy Study Groups would likely increase gestational diabetes mellitus prevalence to 15-20%, because of both a 1-step testing policy and the requirement for only 1 elevated glucose value for diagnosis. Increasing gestational diabetes mellitus prevalence relates to older maternal age and the increasing prevalence of overweight and obesity. This increased gestational diabetes mellitus prevalence is consistent with 29.3% prevalence of prediabetes and 4.5% prevalence of known diabetes outside pregnancy in US adults from 20-44 years of age. Gestational diabetes mellitus according to the International Association of Diabetes in Pregnancy Study Groups criteria is associated with almost twice the risk of large-for-gestational-age babies, increased fetal adiposity, neonatal hyperinsulinemia and preeclampsia, and a 50% higher risk of preterm delivery and shoulder dystocia. The recent publication of the Hyperglycemia and Adverse Pregnancy Outcome Follow Up Study provides further evidence regarding the influence of gestational diabetes mellitus on long-term maternal and infant health. This study clearly demonstrates that hyperglycemia in pregnancy, untreated and identified post hoc by the International Association of Diabetes in Pregnancy Study Groups criteria, carries a 41.5% risk of maternal prediabetes (odds ratio, 3.72; 95% confidence interval, 3.09-4.47) and 10.7% risk of type 2 diabetes (odds ratio, 7.63; 95% confidence interval, 5.33-10.95) after 11.4 years of follow up. Gestational diabetes mellitus was also associated with higher rates of childhood overweight and obesity (prevalence 39.3% with maternal gestational diabetes mellitus; odds ratio, 1.5; 95% confidence interval, 1.56-2.44). This article places these findings in the context of other recent studies that have demonstrated that interventions that include lifestyle measures and/or metformin offer a >50% reduction in the risk of women with gestational diabetes mellitus experiencing the development of overt diabetes mellitus after their index gestational diabetes mellitus pregnancy. Although prevention of obesity and prediabetes in offspring by pregnancy treatment of gestational diabetes mellitus has not been demonstrated to date, we argue that the immediate pregnancy benefits and opportunities for long-term improvements in maternal health justify a reevaluation of the current ambivalent approach taken by the American College of Obstetricians and Gynecologists to gestational diabetes mellitus diagnosis, which currently allow for a choice of alternative criteria. The Carpenter-Coustan or National Diabetes Data Group criteria, listed as preferred criteria by American College of Obstetricians and Gynecologists, markedly limit the frequency of gestational diabetes mellitus in comparison with the International Association of Diabetes in Pregnancy Study Groups criteria and limit the opportunity for immediate and long-term follow up and treatment. We consider that new information from the Hyperglycemia and Pregnancy Outcome Follow Up Study and other recent publications on long-term maternal and offspring risk provides compelling arguments for a more comprehensive approach to the promotion of maternal and infant health through all the life cycle.