Date of Award
Open Access Dissertation
The postpartum period is a unique time for women, where many women experience changes in sleep and activity patterns. Sleep, physical activity, and sedentary time have all been associated with health outcomes, but there is limited research on how these behaviors change throughout the postpartum period. The purpose of the first aim (Study 1) of this dissertation was to examine trajectories of sleep characteristics in Black and White women during the first year postpartum and to examine if there were any racial differences. The purpose of the second aim (Study 2) was to examine trajectories of the percentage of time spent in physical activity, sedentary time, and sleep in a day, in the first year postpartum and to examine the effects of reallocating time from one behavior to another on body weight and fat in the first year postpartum.
The two studies were conducted using data from the Postpartum Weight and Sleep study, a prospective cohort study. Sleep and physical activity were measured via actigraphy at 6-8 weeks, 4 months, 6 months, 9 months, and 12 months postpartum. Body weight was measured at each timepoint. Percent body fat was measured at 6-8 weeks, 6 months, and 12 months using the dual-energy X-ray absorptiometry scan.
Results from the first study showed nighttime total sleep time to increase from 6-8 weeks to 4 months postpartum. Percent sleep and wake after sleep onset (WASO) improved from 6-8 weeks to 6 and 9 months, respectively. While there were improvements in total sleep time and sleep quality, average WASO remained >45 minutes and sleep efficiency
Results from the second study showed participants spent the majority of their day sedentary, followed by sleeping, then in light physical activity (LPA), and moderate to vigorous activity (MVPA) accounted for the smallest proportion of their day. Trajectories of the percentage of the day spent sleeping did not change significantly throughout the first year postpartum. Both Black and White women increased the percentage of their day spent in MVPA. Trajectories of the percentage of the day spent in sedentary behavior (SED) and LPA differed between races. Black women had no significant changes in SED or LPA and White women had a decrease in the percentage of their day in SED and an increase in the percentage of their day in LPA. In cross-sectional analyses, reallocating time from MVPA to LPA was associated with a decrease in body weight in both Black and White women in early postpartum. However, longitudinal analyses from 6-8 weeks to 12 months postpartum found replacing time from sleep, SED, or LPA to MVPA was associated with weight loss in Black women.
Overall, this dissertation found improvements in sleep quality and increases in physical activity throughout the first year postpartum. However, sleep quality remained poor throughout the postpartum period and participants spent the majority of their day sedentary. Further investigations on how these behavioral changes are related to health outcomes are needed.
Kishman, E. E.(2023). Sleep, Physical Activity, and Sedentary Time in the First Year Postpartum. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/7386
Available for download on Sunday, August 31, 2025