Due to a changed lifestyle with less physical activity, unfavorable diets rich in fat and calories and obesity, the prevalence of diabetes mellitus is increasing worldwide. The diabetes epidemic is associated with significant personal and socio-economic consequences. Despite attempts to prevent the complications of diabetes, this disease is still the leading cause of blindness, chronic renal insufficiency and non-traumatic amputation. It is important to detect early on an increase in blood sugar and treat it accordingly to reduce costs and to minimize the personal suffering of those affected. As the number of patients with type 2 diabetes mellitus continues to rise, the number of young women with gestational diabetes mellitus (GDM) also increases. This is a disorder og glucose metabolism, which occurs for the first time in pregnancy. The causes for this are manifold. Among other causes, the increasing age of the mothers and weight gain during pregnancy are risk factors for gestational diabetes. Although it has been recommended that women with gestational diabetes should be re-examined after the birth of their child, many women have not. The study is a follow-up study to clarify whether insulin secretion disorder in women with and after GDM is a risk factor for the occurrence of type 2 diabetes mellitus.