To investigate factors contributing to the sustained domestic violence screening and support practices of Maternal and Child Health nurses 2 years after a randomized controlled trial.Domestic violence screening by healthcare professionals has been implemented in many primary care settings. Barriers to screening exist and screening rates remain low. Evidence for longer term integration of nurse screening is minimal. Trial outcomes showed sustained safety planning behaviours by intervention group nurses.Process evaluation in 2-year follow-up of a cluster randomized controlled trial.Evaluation included a repeat online nurse survey and 14 interviews (July-September 2013). Survey analysis included comparison of proportionate group difference between arms and between trial baseline and 2 year follow-up surveys. Framework analysis was used to assess qualitative data. Normalization Process Theory informed evaluation design and interpretation of results.Survey response was 77% (n = 123/160). Sustainability of nurse identification of domestic violence appeared to be due to greater nurse discussion and domestic violence disclosure by women, facilitated by use of a maternal health and well-being checklist. Over time, intervention group nurses used the maternal checklist more at specific maternal health visits and found the checklist the most helpful resource assisting their domestic violence work. Nurses' spoke of a degree of 'normalization' to domestic violence screening that will need constant investment to maintain.Sustainable domestic violence screening and support outcomes can be achieved in an environment of comprehensive, nurse designed and theory driven implementation. Continuing training, discussion and monitoring of domestic violence work is needed to retain sustainable practices.