Abstract MP72: Intrinsic Motivation is Associated With Greater Physical Activity and Less Sedentary Behavior During Early Pregnancy

Background: National guidelines recommend physical activity (PA) during pregnancy for optimal cardiovascular and overall health. Yet most individuals do not engage in sufficient PA and motivation for PA during pregnancy is poorly understood. Methods: We examined intrinsic motivation for PA (i.e., engaging in activity for enjoyment or satisfaction) and its cross-sectional associations with PA, by intensity level, in the first trimester of pregnancy. Data come from the Pregnancy, Lifestyle and Environment Study (PETALS), a population-based cohort study set in an integrated health system. Following recruitment at 10-13 weeks’ gestation, participants ( N =472; 71% from racial/ethnic groups other than White) completed the validated Behavioral Regulation in Exercise Questionnaire-2 (BREQ-2, intrinsic subscale); and Pregnancy Physical Activity Questionnaire (PPAQ) to estimate typical PA in the prior 2 months, as expressed in MET [metabolic equivalent] hours/week (by intensity and, for MVPA, by domain—i.e., limited to intentional activity such as sports, walking, aerobic exercise, etc.). Data were collected in 2017-18. Results: As hypothesized, intrinsic motivation was higher among those who met ( n =192, 40.7%) vs. did not meet national guidelines for 150 minutes/week of moderate-to-vigorous intensity PA (MVPA; mean BREQ-2 scores [SD]: 2.84 [0.89] vs. 1.94 [1.02], p <0.0001). Likewise, intrinsic motivation was higher among those who scored at or above ( n =131, 27.8%) vs. below the sample-specific 75 th percentile for vigorous PA (2.86 [0.93] vs. 2.09 [1.03], p <0.0001); and lower among those who scored at or above ( n =119, 25.2%) vs. below the 75 th percentile for sedentary behavior (1.99 [1.14] vs. 2.41 [1.01], p =0.0005). Intrinsic motivation was not associated with reaching the 75 th percentiles for total, light, or moderate PA. In modified Poisson regression models adjusted for age, pre-pregnancy body mass index, race/ethnicity, education, and parity, a 1-unit increase in BREQ-2 score was associated with an increased probability of meeting or exceeding MVPA guidelines (rate ratio [95% CI]: 1.66 [1.48, 1.86]) and scoring at or above the 75 th percentile for vigorous PA (1.70 [1.44, 1.99]). A 1-unit increase in BREQ-2 score decreased the probability of scoring at or above the 75 th percentile for sedentary behavior (0.79 [0.67, 0.92]). Conclusions: Only 4 in 10 participants met national guidelines for MVPA in the first trimester of pregnancy. Intrinsic motivation was associated with greater MVPA and vigorous PA, and less sedentary behavior, in this diverse sample. Intrinsic motivation is potentially modifiable and thus a promising target for new behavioral interventions to improve maternal cardiovascular health.