A proposed classification of diabetes mellitus in pregnancy.

Pregnancies complicated by diabetes mellitus are at increased risk of adverse perinatal outcomes. The American College of Obstetricians and Gynecologists recommends universal screening for gestational diabetes mellitus during pregnancy at 24 to 28 weeks of gestation. However, there is controversy on the utility of screening or identification of patients with early gestational diabetes mellitus. In this clinical perspective, an evidence-based classification of diabetes in pregnancy (ie, diagnostic criteria for standard gestational diabetes mellitus vs early gestational diabetes mellitus vs pregestational diabetes mellitus) has been provided to help define subgroups along the spectrum of glucose intolerance/insulin resistance to inform future outcome-based studies.