Early gestational OGTT glucose concentrations were further associated with impaired insulin sensitivity and beta cell dysfunction, as well as the requirement for insulin in later pregnancy.<h4>Conclusions/interpretation</h4>Although the accurate diagnosis of GDM before 24 weeks remains an ongoing discussion, dynamically assessed glucose concentrations during an early OGTT were closely associated with impaired glucose homeostasis and showed good predictive accuracy for later development of GDM as well as the requirement for insulin. The gene discussed is INS; the disease is gestational diabetes.