Gestational diabetes mellitus is defined as glucose intolerance that is first detected during pregnancy.¹ This simple definition belies the complexity of a condition that spans a spectrum of glycemia, pathophysiology, and clinical effects and for which there is a wide diversity of opinion regarding detection and clinical management. There is convincing evidence that mild maternal hyperglycemia is a risk factor for fetal morbidity,² but that morbidity occurs only in a minority of cases. Failure to recognize and treat the condition will result in unnecessary morbidity in some pregnancies, whereas overly aggressive approaches to detection and treatment will result in unneeded . . .