Longitudinal Associations Between Intrinsic Motivation and Subsequent Postpartum Health Behaviors and Life's Essential 8: Results of the Pregnancy, Lifestyle and Environment Study-2 (PETALS-2) Cohort

Background: Cardiovascular health is affected by health behaviors, but postpartum behavioral influences are not well understood. We examined whether intrinsic motivation (IM) is longitudinally associated with long-term postpartum health behaviors (healthy eating, physical activity, self-weighing) and cardiovascular health (Life's Essential 8 [LE8] scores). Methods: The prospective Pregnancy, Lifestyle and Environment Study-2 (PETALS-2) followed women enrolled in the PETALS study at Kaiser Permanente Northern California during pregnancy (N=311). Data were collected via validated self-report surveys and objective measurements during pregnancy and 6-24 months postpartum (2017-2021). Health behaviors were dichotomized by sample-specific 75th percentiles (P75) or pre-specified thresholds (attaining guideline-recommended moderate-to-vigorous physical activity [MVPA, {greater than or equal to}150 minutes/week]; self-weighing regularly [{greater than or equal to}once/week]). Separate analyses lagged IM by timepoint to assess longitudinal associations between behavior-specific IM and immediate subsequent health behaviors; and between an IM composite and immediate subsequent LE8 scores. Results: Each one-unit higher IM score was associated with greater likelihood of Healthy Eating Index-2015 scores {greater than or equal to}P75 at 24 months postpartum (RR=1.42; 95% CI=1.07, 1.88); attaining MVPA guidelines at 6 (1.48; 1.03, 2.12), 12 (1.85; 1.26, 2.71), and 24 months postpartum (1.66; 1.22, 2.27); and regular self-weighing at 6 (1.53; 1.03, 2.27) and 12 months postpartum (1.65; 1.15, 2.36). Each one-unit higher composite IM score was associated with higher LE8 scores at 6, 18, and 24 months postpartum (18-month mean estimate=2.34; 95% CI=0.67, 4.02). Conclusions: Greater IM was associated with healthier behaviors and cardiovascular health through 24 months postpartum. Future research should test whether interventions targeting IM improve health behaviors and long-term maternal cardiovascular health.