Recruiting participants is a fundamental part of clinical research studies, but it’s rarely easy. Any researcher who has managed a study involving human participants can relate to the hurdles we face in meeting recruitment goals – endless hours spent creating outreach materials, drafting phone scripts, and finding locations to post flyers. These challenges are multiplied when it comes to recruiting specific populations, such as pregnant patients; and it can be even more difficult to recruit pregnant patients with obesity due to sensitivity surrounding weight-related issues.

Few studies have specifically explored the recruitment and retention of pregnant patients with obesity. Our study, conducted in the University of Florida’s Department of Health Outcomes and Biomedical Informatics,  sought to fill this gap by investigating whether there are notable differences in enrollment outcomes between mothers with normal weight and mothers with obesity.

The study: A Multi-Channel Approach to Recruitment:  To recruit participants, we employed a range of strategies. We advertised on Facebook, distributed flyers in community locations, had lab members spread the word to pregnant patients, and emailed potential participants via advocacy groups. To be eligible, participants had to over 18, pregnant but not past 36 weeks gestation, and planning to deliver locally. Since this was a longitudinal study, participants would be followed for a year after giving birth, which required them to attend in-person visits throughout that time. Our goal was to assess whether enrollment outcomes differed between mothers with normal weight and those with obesity. We tracked three metrics: 1) eligibility for the study, 2) consent to participate, and 3) completion of study requirements.

What We Found: Difference in Recruitment and Retention: A total of 2,770 people expressed interest in participating in our study. While we couldn’t track how every participant heard about the study (due to missing data), we did find that Facebook was the most effective platform for reaching mothers with obesity. In contrast, flyers were the best tool for reaching mothers with normal weight. When we compared the two groups, we observed significant differences. Pregnant patients with obesity were significantly less likely to consent to participate and less likely to complete the study’s requirements. These findings highlight the unique challenges associated with recruiting and retaining participants from this population.

Key Takeaways: How Our Findings Can Guide Future Recruitment Efforts: Many studies report recruitment outcomes with descriptive data, simply noting differences between groups. However, our study went further by statistically testing these differences between groups. Like any study, ours has limitations. One limitation was that we only used Facebook as our social media recruitment channel; expanding to other platforms could have broadened outreach.  Additionally, since this was a year-long longitudinal study, the study protocol requirements may have deterred some participants, especially those from more vulnerable populations.  Despite these limitations, our findings offer valuable insights.

Recruitment is a crucial aspect of any study, and knowing how to allocate resources for participant recruitment effectively can make a significant difference, especially when working with hard-to-reach populations like pregnant women with obesity. Our study offers practical guidance for future researchers aiming to improve recruitment strategies and ensure diverse representation in maternal health research. By sharing these insights, we hope to help other investigators plan more efficient recruitment efforts, ultimately leading to better studies and improved outcomes for mothers and babies alike.

Link to publication: https://www.nature.com/articles/s41366-024-01625-0

Figure 1: A recruitment flyer for a longitudinal study of pregnancy and obesity.