How to improve recruitment to pregnancy trials: learning from the experiences of participants and refusers

Abstract

Background: Diet in pregnancy has health implications for both mothers and babies, and pregnancy is a time when women may be open to making lifestyle changes to improve their health. Yet only a third of eligible pregnant women agreed to participate in a dietary intervention trial. This study aims to understand why. Methods: Pregnant women were invited to participate in a trial of vitamin D supplementation. 194 of those who refused to participate completed a questionnaire identifying their reason for declining. Of those, 30 agreed to a telephone interview. Of the 169 women who have completed the trial to date, 30 have been interviewed face-to-face. All interviews were tape-recorded and analysed thematically. Findings: Questionnaire data identified the most common reasons for refusing to participate: being too busy (n=57); and study requirements including taking tablets (n=57), bone scans (n=46), or blood tests (n=45). Analysis of the interview data showed that personal factors and beliefs about medical research influenced women’s perceptions of the study requirements and shifted the decisional balance towards or away from participating. Refusers tended to express a mistrust of medical research. Discussion: Adequate trial sample size is essential for generating a strong evidence base for health recommendations and services. Health psychologists have a key role in maximising recruitment, by identifying and addressing factors that influence non-participation, and by designing study materials and publicity that emphasise reasons to trust medical research. More data should be collected from those who refuse to participate in trials to supplement this almost unique data-set.