(1016) How to Efficiently Recruit Participants in a Perinatal Cohort Study; CAN-B Cohort Strategies/Lessons Learned

Objective: Recruitment processes in perinatal cohort remain challenging, particularly when a specific population such as cannabis consumers is involved. The CAN-B study aims to determine the impact of prenatal cannabis exposure on fetal brain and infant neurodevelopment with longitudinal follow-up of mother/infant from pregnancy until 2y post-natal. Here we share our experience in finding the best recruitment strategy to meet our enrollment objective.

Study Design: From May 2022 to May 2024, at the routine 1^st trimester scan at the obstetrical ultrasound unit of Sherbrooke University Hospital Center (CHUS), 4 recruitment strategies were successively tried: 1) study flyer given by care providers (May-September 2022), 2) by phone (October-November 2022),  3) study flyer given by care providers or part time in-person presentation of the study by research team (December 2022-May 2023) and  4) full time in-person presentation of the study by research team (June 2023 to May 2024). Interest and enrollment rate were compared.

Results: 112 pregnant women were enrolled (71 cannabis users/41 controls). Strategy 4 triggered the highest basic interest to participate in a clinical research compared to the other strategies (87% vs < 64%) and yielded the highest enrollment rate (80%) compared to strategies 1(67%), 2 (40%) and 3 (70%). Ultimately, the last strategy with full time direct personalized approach allowed us to double our monthly enrollment rate of cannabis users. Same strategies performances were observed for the recruitment of controls.

Conclusion: Recruitment of cannabis users in the CAN-B cohort showed that low-cost passive strategies (e.g. flyers) or relying only on care providers appeared to be much less efficient and not cost-effective. Although costly, direct personal contact by research professional integrated into routine care is the best strategy to prioritize for recruiting pregnant women. This experience provides useful information for clinical researchers in designing perinatal cohorts.