BACKGROUND: The Dutch Obstetric Telephone Triage System (DOTTS) was developed to improve the quality of acute obstetric care. To achieve optimal effect, DOTTS should be adopted in the daily care process by triage staff. OBJECTIVE: The aim of this study was primarily to evaluate the degree of implementation (i.e., normalization) of the DOTTS and secondarily to evaluate which lessons can be learned from its current implementation in Dutch hospitals. METHODS: An evaluation study with a mixed methods design was performed. All triage staff in nine Dutch hospitals who implemented DOTTS before 1 September 2019 were invited to complete the Normalization MeAsure Development (NoMAD) questionnaire between December 2019 and July 2020. The questionnaire is based on the Normalization Process Theory. This self-report questionnaire gives insight into the work people do in order to integrate and embed new practice in routine care. NPT is based on four constructs: coherence, cognitive participation, collective action and reflexive monitoring. Within the questionnaire each construct is represented by 4-7 questions. Questions could be scored on a 5-point Normalization Process Score. Descriptive statistics were used for analysis of questionnaire scores. Subsequently, analysis of questionnaires were discussed during a focus group. Template analysis following the four constructs of NPT was used for analyzing the results of the focus group. RESULTS: In total 173 out of 294 (59%) triage-staff members completed the NoMAD-questionnaire. Ninety percent of the participants had used DOTTS for over six months. The digital application was used as much as possible or always by 137 out of 173 participants (79%). The overall Normalization Process Score was 3.77 (SD=0.36). The constructs Coherence and Cognitive Participation scored 4.01 (SD=0.47) and 4.05 (SD=0.45) respectively. Collective Action scored 3.5 (SD=0.45) and Reflexive Monitoring scored 3.72 (SD=0.47). Analysis of the focus group discussion showed that the added value of DOTTS was seen ...