BACKGROUND:The treatment of diabetes in pregnancy has potentially far-reaching benefits for both pregnant women with diabetes and their children and may provide a cost-effective approach to the prevention of obesity, type 2 diabetes mellitus, and metabolic syndrome. Early and accurate diagnosis of diabetes in pregnancy is necessary for optimizing maternal and fetal outcomes.CONTENT: Optimal control of diabetes in pregnancy requires achieving normoglycemia at all stages of a woman's pregnancy, including preconception and the postpartum period. In this review we focus on new universal guidelines for the screening and diagnosis of diabetes in pregnancy, including the 75-g oral glucose tolerance test, as well as the controversy surrounding the guidelines. We review the best diagnostic and treatment strategies for the pregestational and intrapartum periods, labor and delivery, and the postpartum period, and discuss management algorithms as well as the safety and efficacy of diabetic medications for use in pregnancy.