There are two entities to differentiate: 1. Diabetes in pregnancy (pre-existent type 1 or type 2 diabetes with tendency of deterioration during pregnancy or first occurrence of a type 1 or type 2 diabetes with persistence after pregnancy. 2. Impaired Glucose Tolerance = IGT (Diagnosis of an impairment of glucose tolerance during pregnancy) Aims of the screening are the avoidance of complications for mother and child. There is no uniform consent regarding screening during pregnancy. With pregnant women without risk factors, the blood sugar is determined without eating and drinking in plasma between 24 and 28 weeks of gestation. If values are > 4.8 mmol/l, an oral 75 g glucose tolerance test is carried out. Alternatively, a 50 g oral glucose tolerance test can be made. With pregnant women with risk factors, we already carry out an oral 75 g glucose tolerance test in the first trimester. If the values are normal, we repeat the 75 g glucose tolerance test between 24 and 28 weeks of gestation. Main pillars of therapy are diet and movement. In gestational diabetes, an insulin therapy is indicated if blood sugars are too high, fetal growth is sonographically accelerated or a polyhydramnion is present. Oral antidiabetic medicaments are contraindicated during pregnancy. Pregnancies with diabetes in pregnancy or gestational diabetes are risk pregnancies, which are controlled more intensively. Delivery is ideally at term or with confirmed lung maturity. If an impaired glucose tolerance is diagnosed during pregnancy, an oral 75 g glucose tolerance test as well as annually blood sugar controls are carried out because of the augmented risk of developing a type 2 diabetes later in life.