Gestational diabetes mellitus (GDM) has historically been perceived as a medical complication of pregnancy that also serves as a harbinger of maternal risk of developing type 2 diabetes mellitus (T2DM) in the future. In recent decades, a growing body of evidence has detailed additional lifelong implications that extend beyond T2DM, including an elevated risk of ultimately developing cardiovascular disease. Furthermore, the risk factors that mediate this lifetime cardiovascular risk are evident not only after delivery but are present even before the pregnancy in which GDM is first diagnosed. The concept thus emerging from these data is that the diagnosis of GDM enables the identification of women who are already on an enhanced track of cardiometabolic risk that starts early in life. Studies of the offspring of pregnancies complicated by diabetes now suggest that the earliest underpinnings of this cardiometabolic risk profile may be determined in utero and may first manifest clinically in childhood. Accordingly, from this perspective, GDM is now seen as a chronic metabolic disorder that holds implications across the life span of both mother and child.