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

Area of Science:

• Obstetrics and Gynecology
• Clinical Research Methodology
• Perinatal Health

Background:

• Recruiting pregnant women for clinical studies, particularly those involving substance use, presents unique challenges.
• The Cannabis Antenatal and Neurodevelopment of Babies (CAN-B) study aimed to enroll pregnant individuals, including cannabis users, to investigate perinatal outcomes.

Purpose of the Study:

• To identify and compare the effectiveness of different recruitment strategies for a cohort study involving pregnant women.
• To evaluate interest, enrollment rates, and cost-efficiency of various recruitment approaches.

Main Methods:

• Four recruitment strategies were successively implemented at the Sherbrooke University Hospital Center (CHUS) from May 2022 to August 2025.
• Strategies included flyers, phone recruitment, and in-person presentations by research staff, with varying levels of direct interaction.
• Data on participant interest, enrollment numbers, and cost-effectiveness were collected and compared across strategies.

Main Results:

• A total of 185 participants were enrolled, with 115 identified as pregnant cannabis users.
• The full-time in-person presentation strategy yielded the highest enrollment rate (3 users/month) and high interest (71%).
• Phone recruitment was the most expensive strategy with suboptimal performance, while flyers were least costly but less effective.

Conclusions:

• Pregnant women, including cannabis users, show significant interest in participating in clinical research.
• Active recruitment strategies involving direct interaction between research staff and participants are crucial for increasing both interest and enrollment rates in perinatal studies.