Recruitment of healthy third-trimester pregnant women and their newborns into a prospective dental study at a primary health care clinic

BACKGROUND: Recruiting and retaining mother-infant dyads in clinical research is often complex, particularly in socioeconomically disadvantaged and ethnically diverse communities. This paper reports on the recruitment and retention strategies employed within a prospective longitudinal cohort study (First Tooth Study) that investigated the oral colonization of Candida albicans and Streptococcus mutans as risk factors for Severe Early Childhood Caries (S-ECC) and the vertical transmission of these oral microorganisms. The study population was underserved mother-infant dyads, a group historically challenging to engage and retain due to factors such as socioeconomic barriers, busy schedules, and logistical challenges, which were further complicated by the COVID-19 pandemic. Few studies have systematically described recruitment and retention strategies for this population in the context of oral health research. AIM: The purpose of this paper is to describe and evaluate the recruitment and retention strategies used to enroll and maintain 186 third-trimester pregnant women and their infants within a primary care setting, and to assess the relative efficiency of each approach based on enrollment conversion rates, contribution to overall recruitment, and time allocation. METHODS: Participants were recruited from two facilities of the University of Rochester: Highland Family Medicine (HFM), and the Perinatal dental clinic at Eastman Institute for Oral Health in Rochester, NY using a combination of direct recruitment, community networking, and outreach within prenatal groups. Retention efforts included scheduling study visits alongside routine pediatric appointments to reduce participant burden, offering financial incentives, and implementing a Reminder, Recall, and Outreach (RRO) system managed by a dedicated outreach worker. During the COVID-19 pandemic, additional adaptations were made, including offering home visits and curbside data collection, to maintain participant safety and adherence. RESULTS AND CONCLUSION: Over 27 months, the study successfully enrolled 186 mother-infant dyads, meeting the recruitment target despite initial challenges and COVID-19 disruptions. Retention rates remained high, with an approximate 15% annual attrition during the two-year follow-up period, attributed to strategic visit alignment, personalized outreach, and practical supports like parking vouchers and home visits. The study underscores the importance of customized recruitment and retention strategies in overcoming socioeconomic and logistical barriers in underserved populations. Findings contribute valuable insights into best practices for engaging mother-infant dyads in longitudinal oral health research.