Diabetes mellitus gestacional (DMG) is defined as any level of glucose intolerance that is recognized for the first time during pregnancy, typically diagnosed between weeks 24 and 28. The document outlines the classification, epidemiology, etiology, pathophysiology, risk factors, diagnostic criteria, and screening recommendations for DMG, noting that obesity, advanced maternal age, and a history of DMG increase risk. Treatment involves dietary management and monitoring blood glucose, with insulin therapy as necessary, tailored to individual needs.