The Association of Physical Activity During Pregnancy and Postpartum Weight Retention: A Retrospective Cohort Study

This study aimed to identify physical activity trajectories through pregnancy and examine associations with postpartum weight retention.

We included pregnancies from one health care system from 2009 to 2020. Data were collected from electronic health records and physical activity from self-report before pregnancy and during each trimester. High, medium, and low physical activity groups were identified using discrete trajectory analysis. The outcome was the percentage of postpartum weight retention in the first year after pregnancy, measured as postpartum BMI as a percentage of prepregnancy BMI. All postpartum BMI measures from 21 through 365 days were analyzed using mixed effects regression models using R version 4.4.1.

Among 58,828 pregnancies, 54.7% were in Hispanic participants, 24.8% White, 10.3% Asian/Pacific Islander, 9.0% Black, and 1.3% other. Mean BMI after delivery was 105.2% ± 8.9% of prepregnancy BMI. Physical activity trajectories were high (3.4%), medium (64.9%), and low (31.6%). Compared with the low and medium physical activity trajectories, individuals in the high physical activity trajectory had greater odds of achieving prepregnancy BMI (OR: 1.314; 95% CI: 1.172-1.472 and OR: 1.285; 95% CI: 1.149-1.436, respectively).

Individuals with high physical activity from preconception through pregnancy have less weight retention at 360 days post partum than women with lower physical activity.