BACKGROUND: There is a need to better understand barriers to recruitment and participation in randomized controlled trials (RCTs) evaluating postpartum thromboprophylaxis, as previous trials had low recruitment and were not feasible. In a qualitative interview study of the pilot PARTUM trial (a feasibility trial of low-dose aspirin versus placebo for six weeks postpartum), we explored the facilitators and barriers to trial involvement. METHODS: Patients eligible for the pilot PARTUM trial, including those who declined joining the trial, were invited to participate in a qualitative study. Physicians whose clinical practice included caring for eligible patients were also invited to participate. Thirty-minute semi-structured interviews were conducted by two researchers. Data were analyzed iteratively using reflexive thematic analysis. RESULTS: There were 19 patient and 13 physician interviews conducted at a single Canadian centre. Nine pilot PARTUM participants and 10 non-participants were included. Patients identified the simple study design and familiar oral medication ('Participating as an Easy Ask') and helping other parents ('Helping Other Parents by Providing Knowledge') as facilitators to participate in the trial. Most patients invoked altruism
however, their decision to participate in the trial was influenced by their perception of VTE risk ('VTE Risk Perception and Communication'), their birth experience ('Birth Experience Informs Perspective'), and opinion of their obstetrical care provider ('Engaging Trusted Care Providers'). CONCLUSION: Trial participation is uniquely affected by experiences during pregnancy, delivery, and new parenthood. Improved understanding of the factors most important to patients will inform the design and conduct of future patient-focused clinical trials.