Twenty-six years ago the St. Vincent Declaration aimed for an achievement of a comparable pregnancy outcome in diabetic and non-diabetic women. However, current surveys clearly show that women with pre-gestational diabetes still feature a much higher risk of perinatal morbidity and even increased mortality. This fact is mostly ascribed to a persistently low rate of pregnancy planning and pre-pregnancy care with optimization of metabolic control prior to conception. In addition, obesity increases worldwide, contributing to a growing number of women with type 2 diabetes at a childbearing age, and a further deterioration in outcome in diabetic women. Development of diabetic embryopathy and fetopathy are known to be related to maternal glycemic control (target: normoglycemia and normal HbA1c, if possible without hypoglycemia). The risk for hypoglycemia is at its greatest in early pregnancy and decreases with the progression of pregnancy due to the hormonal changes leading to a marked increase of insulin resistance. Intensified insulin therapy with multiple daily insulin injections and pump treatment are equally effective in reaching good metabolic control during pregnancy. All women should be experienced in the management of their therapy and on stable glycemic control prior to the conception. In addition, thyroid dysfunction, hypertension as well as the presence of diabetic complications should be excluded before pregnancy or treated adequately in order to decrease the risk for a progression of complications during pregnancy as well as for maternal and fetal morbidity.