Facilitators and Barriers to Prenatal Exercise from the Biopsychosocial Perspective of Pregnant Individuals: “If You Keep Moving, Then You Won't Stop”

INTRODUCTION: Exercise during pregnancy benefits maternal and fetal health, yet many pregnant individuals struggle to maintain regular physical activity. Biological, psychological, and social factors, along with structural determinants of health, shape engagement, particularly among populations historically underrepresented in prenatal exercise research. METHODS: This secondary analysis of the Prenatal Heart Smart trial examined motivational interviews from 108 pregnant individuals participating in a low-intensity exercise intervention involving walking or stretching 5 days a week during the last 10 weeks of pregnancy. Weekly motivational interviews evaluating importance and confidence ratings for exercise were collected on a 0 to 10 scale. Qualitative data were analyzed using content analysis, and quantitative data were analyzed descriptively. RESULTS: Participants rated exercise as highly important (mean [SD], 8.46 [1.71]) and expressed moderate-to-high confidence in engaging in it (mean [SD], 7.70 [1.98]). Fatigue, pain, and discomfort were common barriers, whereas accessible, home-based activities supported engagement. Psychological barriers included fear of overexertion, uncertainty about safety, and fluctuating motivation, whereas intrinsic motivation, stress relief, and routine formation facilitated consistency. Social support from partners, family, and health care providers encouraged participation, although many cited limited provider guidance and competing responsibilities as challenges. Structural determinants such as work demands and neighborhood safety further shaped engagement. DISCUSSION: Exercise during pregnancy is influenced by intersecting biological, psychological, social, and structural factors. Pregnant individuals may value exercise but lack the confidence, resources, and systemic support necessary to sustain it. Interventions should extend beyond education to include culturally responsive, accessible, and community-based approaches that strengthen confidence, social support, and structural equity to promote sustainable prenatal physical activity.