Abstract Aims and objectives the aims of the study were to explore the experience of maternity care services used by women whose pregnancy is complicated by pre-existing diabetes, to gain a deeper understanding of service use and to identify aspects of services that women with pre-existing diabetes would like improved. Background for women with pre-existing diabetes; pregnancy, birth and the transition to motherhood can be complex and even chaotic. The aim of specialist diabetes care given during pregnancy and delivered by a specialist team of health-care professionals is to optimise pregnancy outcome. However, how health-care professionals within maternity services provide care and support women with pre-existing diabetes during pregnancy and early motherhood has received limited attention. Design an exploratory study utilising a grounded theory approach was conducted. Data were collected via in-depth interviews with 20 respondents; one-to-one, dyad and group interviews were undertaken to fully explore issues. Analysis was undertaken by sub-groups of the research team with at least two members working on each of them. Findings three themes were identified from interviews: empathic care with care more focused on diabetes not pregnancy; feeling judged by health-care professionals (with nearly all respondents reporting negative encounters of consultation with the specialist team); and the notion of expertise (with respondents reporting feeling frustrated when it seemed health-care professionals did not value their expertise). Conclusions the study emphasised the importance of the health-care relationship for pregnant women with pre-existing diabetes. For outcomes to be optimised women need to be able to form open and trusting relationships with the health-care team. Relevance to clinical practice this study highlights the need for the health-care team not only to provide physical care to optimise outcome but also supportive care to assist women with pregnancies complicated by diabetes to achieve the best possible physical and emotional health and well-being.