Gestational diabetes is the most common metabolic abnormality during pregnancy. In a Swedish population 2-10% of all pregnant women are diagnosed with gestational diabetes mellitus (GDM). The frequency differs dependent of methods for screening and diagnostic references, even within Sweden. Women with GDM have about 50% risk to develop manifest type 2 diabetes (T2DM) within 20 years. Most counties in Sweden have a recommendation to follow women with GDM yearly with an examination and an oral glucose tolerance test (OGTT). Unfortunately, this recommendation often fails, partly due to limited resources at the health care units but also due to lack of compliance from the women. Often after the baby is born focus is changed from the mother to the child and only 30.7% of the women with one or more risk factors performed an OGTT, despite stipulated OGTT in local guidelines. The diagnose GDM is under debate and Sweden has started to implement the recommendations from World Health Organisation (WHO) from 2013 with a lower cut-off for GDM, which will increase diagnostic sensitivity and consequently increase the number of women diagnosed with GDM. The plan was to conduct a randomized, clinical trial testing implementation the new recommendations in Sweden step-wise from 2018 and onwards. The recruitment is now complete and the results are expected to be published in 2021. The overarching aim of this study is to conduct a randomized, controlled clinical trial to test the effect of a model for a lifestyle intervention in clinical practice, using technical support as well as personal, individual support. The intervention is based on the existing organisation and structure in Primary Care and would thus be inexpensive and straight-forward to implement. An additive aim is to explore background mechanisms for the development of type 2 diabetes in women with gestational diabetes.