Diabetes mellitus during pregnancy can be accompanied by a wide variety of mostly serious complications, which may be: infections, pregnancy induced hypertension, premature labor, congenital anomalies, miscarriages, intrauterine death, macrosomia, intrauterine growth retardation, and premature delivery. A multidisciplinary approach to counseling as well as treatment of the pregnant or, preferentially, preconceptional diabetic woman can reduce these problems or lead to their early recognition. Intensive monitoring of maternal metabolism and fetal well-being during pregnancy by physicians accustomed to the treatment of pregnant diabetics should especially improve fetal outcome.