Recruitment of pregnant women to an exercise-intervention study

We share here our experience of recruiting pregnant women into an exercise intervention study. Recruitment challenges were anticipated owing to the study design, which required four hospital visits for cardiovascular assessment, a long-term (nine-month) commitment, and adherence to a 20-week exercise programme. Fifty-three women were assigned to one of three groups (no-exercise, land exercise or water exercise) using a 2 × 2 × 2 flexible randomisation design. Seven hundred forty-four women were screened at an antenatal clinic, of whom 501 were eligible to participate in the study. One hundred forty-five women were subsequently approached: 46 (32%) of whom agreed to participate, 42 (29%) were interested but then declined and 57 (39%) declined outright. Our study design helped recruit pregnant women as it allowed them some choice of group membership. We also noted that the participant-researcher relationship is important in reducing attrition. Our experience provides indications of likely recruitment and attrition rates for future randomised controlled trials of this type.