Abstract The termination of pregnancy trial (Newcastle upon Tyne, UK), is the only randomised trial on termination of pregnancy methods incorporating a qualitative element that aimed to understand the experiences of women participating in the trial. Based on the results of this qualitative work, this article aims to provide insights into two strands of understanding; firstly, women’s experience of participating in research about abortion and secondly, their experience of participating in a randomised preference trial. Semi-structured interviews were conducted of up to 90 minutes with 30 participants recruited at a single hospital site. A total of 20 women from the preference arm and 10 from the random arm were interviewed. The analysis and discussion of our findings use reflexive modernisation as a framework for understanding and interpreting some of the actions of social agents, that is, the participants and trial recruiters in the course of a clinical trial as an expert system. We found that the factors that shape women’s experiences and decisions include trust in the expert system and reflexivity and agency on the part of both participants and trial recruiters.