Recruiting a geographically, ethnically and socioeconomically diverse population of postpartum women into a behavioural weight management intervention trial: an evaluation of strategies used in the Supporting MumS (SMS) randomised controlled trial

Abstract Background Engaging women in behavioural weight management interventions in the postpartum period has proved challenging. Previous trials of such interventions have frequently experienced issues with participant recruitment and retention and recruited samples have been skewed towards inclusion of women from white ethnicities and more affluent backgrounds. In this paper, we evaluate strategies used to recruit a geographically, ethnically and socioeconomically diverse sample of postpartum women to the Supporting MumS randomised controlled trial (RCT). Methods Two-arm, parallel group, multi-centre RCT. Recruitment took place in five sites across the United Kingdom (UK), selected with consideration of geographic, ethnic and socioeconomic population diversity. Participants were women (including those who gave birth but who do not identify as women), within 6 weeks to 2 years postpartum, with a Body Mass Index of ≥ 25 kg/m 2 . The range of recruitment strategies employed spanned healthcare settings, community settings and social media. Strategies used to recruit over a 12-month period were recorded, and outcomes including numbers expressing interest, screened and randomised, were assessed by site, ethnicity and Index of Multiple Deprivation (IMD) data. Results Over 12 months, 2457 women expressed an interest, 1227 (49.9%) were screened for eligibility and 892 (36.3%) were randomised. The sample included 33.6% of women from minoritised ethnic groups and 53.5% of women who lived in the two most deprived IMD quintiles. Most participants learnt about the study through social media (45.5%), followed by community groups and settings aimed at parents (26.0%), the Born in Bradford’s Better Start ( BiBBS ) cohort (12.5%), friends/family (7.2%), general community settings (5.3%) and healthcare professionals (5.4%). Success of recruitment strategies varied across sites and participant characteristics. Conclusions An ethnically and socioeconomically diverse sample of postpartum women across the four UK countries was recruited within the planned 12-month timeframe. This was achieved by selection of recruitment sites (considering geographical spread and population characteristics), using a range of strategies and tailoring these to local populations, and iteratively adapting strategies employed based on success. Trial registration ISRCTN16299220 ( https://doi.org/10.1186/ISRCTN16299220 ). Prospectively registered on February 10, 2022.