Determinants of moderate-intensity physical activity during pregnancy based on the COM-B model

This study aimed to explore the determinants of moderate-intensity physical activity (PA) among pregnant women using the Capability, Opportunity, Motivation, and Behavior (COM-B) model. A cross-sectional study was conducted with 316 participants recruited from three tertiary hospitals in China. Data were collected through self-reported questionnaires measuring demographic characteristics, PA knowledge, PA social support, PA environment, PA self-efficacy, and moderate-intensity PA. Structural equation modeling was employed for data analysis. Mean moderate-intensity PA was 7.11 ± 6.88 MET-hours/week. Analysis using standardized path coefficients (β) revealed that: PA knowledge had a significant direct effect on moderate-intensity PA (β = 0.265, p < 0.001) and a significant indirect effect mediated by PA self-efficacy (β = 0.035, p = 0.003). PA social support exhibited both a significant direct effect (β = 0.238, p < 0.001) and a significant indirect effect via PA self-efficacy (β = 0.127, p = 0.004) on moderate-intensity PA. PA environment affected moderate-intensity PA directly (β = 0.218, p = 0.003) and also exerted a significant indirect effect through the serial mediators of PA social support and PA self-efficacy (β = 0.205, p < 0.001). Additionally, PA self-efficacy had a significant direct effect on moderate-intensity PA (β = 0.220, p = 0.005). The study revealed a low level of moderate-intensity PA among Chinese pregnant women. In conclusion, PA knowledge, PA social support, PA environment, and PA self-efficacy were significant direct and/or indirect predictors of moderate-intensity PA. These factors represent promising targets for designing effective interventions to promote PA during pregnancy.