Obstetricians
Obstetricians were recruited via social media or via mailing lists from a previous survey. Brief study information was shared via social media, along with contact details of the research team and how to contact the research team. The researcher responded to potential participants via email to send them a participant information sheet and consent form. Participants who returned a completed consent form were then offered a telephone interview. Interviews were conducted between October 2020 and February 2021 using a semi-structured interview schedule and lasted approximately 45 min. The interview covered: (i) acceptability of different techniques; (ii) acceptability and (iii) feasibility of a trial generally as well as the different trial designs (Fig. 