Among 311 postpartum women in the PETALS-2 prospective cohort, each one-unit increase in intrinsic motivation (IM) score was associated with 42% greater likelihood of achieving top-quartile Healthy Eating Index scores at 24 months, 48–85% greater odds of meeting 150 minutes/week moderate-to-vigorous physical activity guidelines across multiple timepoints, and 53–65% greater likelihood of regular self-weighing at 6 and 12 months. Composite IM scores also predicted higher Life's Essential 8 (LE8) cardiovascular health scores at 6, 18, and 24 months postpartum, with an 18-month mean difference of 2.34 points (95% CI: 0.67–4.02).
This finding matters because the postpartum period is a documented inflection point for long-term maternal cardiometabolic risk, yet behavioral intervention research in this window remains sparse. LE8 — the American Heart Association's updated cardiovascular health metric incorporating sleep, diet, activity, weight, blood pressure, lipids, glucose, and smoking — is increasingly validated as a longevity predictor, making its postpartum trajectory clinically meaningful. The motivation-behavior link aligns with Self-Determination Theory, suggesting internal rather than external drivers sustain health behavior change. Critically, this is a preprint not yet peer-reviewed, so findings should be interpreted cautiously. The cohort is Kaiser Permanente Northern California members — relatively insured and health-engaged — limiting generalizability. With only 311 participants and self-reported motivation measures, confounding and measurement bias remain concerns. Still, the consistent longitudinal signal across multiple timepoints is noteworthy and supports designing IM-targeted postpartum interventions.
