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.

Objective To evaluate strategies used to recruit a geographically, ethnically and socioeconomically diverse sample of postpartum women (including those who gave birth but who do not identify as women) to the Supporting MumS randomised controlled trial (RCT). Design Two-arm, parallel, multi-centre RCT. Setting Five sites across the United Kingdom, selected with consideration of geographic, ethnic and socioeconomic diversity. Population or Sample Women, within 6 weeks to two years postpartum, with BMI ≥25 kg/m 2. Methods Strategies used to recruit over a 12-month period were recorded, and outcomes were assessed by site, ethnicity and Index of Multiple Deprivation (IMD) data. Main Outcome Measures Numbers expressing interest, screened and randomised. Results Over 12 months, 2,457 women expressed an interest, 1,227 (49.9%) were screened for eligibility and 892 (36.3%) were randomised. The sample had 33.6% non-white ethnicity and 53.5% lived in the two most deprived quintiles (according to IMD). 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 health 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.