Abstract The current diagnostic criteria for gestational diabetes (GDM) were based on data from women after 24 weeks of gestation, but this may not be equally applicable for earlier gestation. There is insufficient data regarding early pregnancy glycaemia and the associated complications. We retrospectively reviewed 39,483 deliveries and 12,918 with risk factors for GDM underwent oral glucose tolerance test (OGTT) before 24 weeks of gestation. A strong and progressively positive association was observed with any p…