Recruitment and retention of participants with obesity into a longitudinal birth cohort: the Breastfeeding and Early Child Health (BEACH) study

Background

The study aimed to evaluate how maternal pre-pregnant body mass index (BMI) impacts participant recruitment and retention.

Methods

Participants were enrolled in a longitudinal study between 30 and 36 weeks of pregnancy as having normal weight (pre-pregnant BMI ≥ 18.5 and <25 kg/m²) or obesity (pre-pregnant BMI ≥ 30.0 kg/m²). Recruitment channels included Facebook, email, newspaper, phone calls, radio advertisements, flyers, and word-of-mouth. The stages of recruitment included eligibility, consent, and completion. Pearson’s chi-square tests were used to evaluate the relationship between BMI and enrollment outcomes.

Results

Recruitment yielded 2770 total prospective participants. After screening, 141 individuals were eligible, 83 consented, and 60 completed the study. Facebook was the most successful method for identifying eligible pregnant patients with obesity, while a higher percentage of participants recruited through word-of-mouth and flyers consented to the study. Pre-pregnant BMI was significantly associated with the stage of recruitment completed by the participant (p = 0.04), whereby individuals eligible for the study with obesity were less likely to consent and complete study visits.

Conclusion

We demonstrated that maternal obesity was significantly associated with enrollment outcomes in a longitudinal birth cohort study. This study showed that pre-pregnancy BMI influenced study participation. Therefore, tailored recruitment strategies to enhance the recruitment and enrollment of individuals with obesity in maternal-infant health research may be necessary.