<p>The incidence of gestational diabetes mellitus (GDM) is increasing worldwide and affects over 10% of all pregnant women. Gestational diabetes is a form of glucose intolerance which develops during pregnancy and does not fulfill the criteria of manifest diabetes mellitus. The hormonal changes during pregnancy lead to physiological insulin resistance, which can lead to hyperglycemia in predisposed women. The resulting hyperglycemia is then transferred to the fetus via the placenta, which causes fetal hyperinsulinemia. Typical consequences are complications such as macrosomia, neonatal hypoglycemia, erythrocytosis, and respiratory control disorders. Early diagnosis via screening with the 50-gram oral glucose challenge and, if necessary, the 75-gram oral glucose tolerance test (oGTT) is crucial to avoid fetal damage. Ultrasound-based fetal growth monitoring is used to assess the treatment success. Particularly relevant is the fetal abdominal circumference and the abdominal circumference/head circumference ratio. Delivery should be planned in a&#xa0;perinatal center, particularly in the case of GDM necessitating insulin therapy. Early feeding and tight monitoring of blood glucose in newborns are essential to avoid postnatal hypoglycemia. Breastfeeding is strongly recommended, as it protects the health of both mother and child in the long term. Mothers should receive postpartum metabolic follow-up and lifelong aftercare to enable early detection and management of a possibly increased type&#xa0;2 diabetes risk.</p>