The aim is to investigate whether the implementation of a web-based support to women with type 1 diabetes during pregnancy and early motherhood can improve well-being and self management of diabetes. Type 1 diabetes is associated with increased medical risks and increased psychosocial pressure in relation to childbearing. There is need for extended support from both health care professionals and peers. Web-based interventions can improve personal capacity and self-management in people with long- term illnesses but are not evaluated in childbearing women with type 1 diabetes. A web site prototype for full-size browsers and mobile devices has been developed through a participatory design by multidisciplinary researchers, health care professionals, experienced mothers with type 1 diabetes and web designers. In a randomised control study the developed web site offering information, communication with health care professionals, person-centred self-care diaries and online social community of included women, is provided to the intervention group in early pregnancy at admission to specialised antenatal clinics at six hospitals in Sweden. A control group will receive standard care (usual care). Total n = 160. Primary outcomes are Well-Being Questionnaire and Diabetes Empowerment Scale. The intervention offers proactive solutions for strengthening patients' decision making of diabetes in daily life during pregnancy and early motherhood, and is expected to increase their wellbeing, personal capacity and knowledge of diabetes.