Effects of a Postpartum Sleep Schedule on Childless Women's Sleep, Circadian Amplitude, Daytime Sleepiness, Performance, and Mood

Effects of a Postpartum Sleep Schedule on Childless Women’s Sleep, Circadian Amplitude, Daytime Sleepiness, Performance, and Mood Amanda L. McBean, M.S. OBJECTIVES: A complex process of physiological and environmental changes during the postpartum period confounds our understanding of the discrete impacts of postpartum sleep fragmentation. The aim of this dissertation was to isolate the effects of postpartum sleep fragmentation by manipulating the sleep of childless women in the laboratory to model a postpartum sleep fragmentation schedule. Actigraphically and polysomnographically-recorded sleep, daytime functioning, mood, and melatonin amplitude were quantified. METHODS: Eleven healthy, childless women (25.4 [SD±2.3] years, 72.7% white, $23,000 [SD±$11,000] household income) contributed continuous wrist actigraphy and daily psychomotor vigilance test (PVT) for one baseline week followed by 3 consecutive nights of overnight polysomnography: an adjustment/sleep disorder screening night, a baseline night, and a night of experimental sleep fragmentation during which they were awakened 3 times for 30-35mins each. During nocturnal awakenings, women engaged in a standardized protocol that included feeding, changing, and rocking a doll in dim light (<3 lux) to model postpartum motor activity and postures. First-morning baseline and fragmentation night voids were collected for 6-sulphatoxymelatonin assays to estimate circadian rhythm amplitude. Baseline and post-fragmentation Multiple Sleep Latency Tests (MSLT) and Profile of Mood States Surveys (POMS) were administered. A final week of at-home actigraphy monitoring, daily PVTs, and POMS captured recovery. RESULTS: Sleep time did not change between baseline (M=461±28min) and sleep fragmentation nights (M=448±34min; p=.17), while sleep efficiency decreased (M=90.9%±6.1%; M=74.4%±3.9%, respectively; p<.001). Frequency of PVT lapses increased significantly from baseline (M=1.62±1.83) to the week after fragmentation (M=2.72±1.76; p=.01). Mood disturbance increased from baseline (M=-1.00±7.10) to after sleep fragmentation (M=8.55±12.9; p=.037). MSLT scores increased from baseline (M=13.1±3.54) to after sleep fragmentation (M=16.3±3.51; p=.02), indicating decreased daytime sleepiness. No changes in time spent in nocturnal sleep stages, 6sulphatoxymelatonin concentration and actigraphy-defined total sleep time were found after sleep fragmentation compared to baseline. CONCLUSIONS: The current study is the first to experimentally examine the effects of a simulated postpartum sleep disturbance schedule on aspects of physiology and behavior. Results suggest no changes in measured physiological components of a single night of simulated postpartum sleep fragmentation, but significant deficits in mood and neurobehavioral performance. Disruption of sleep continuity in the absence of measured physiological changes may be sufficient to cause poorer mood and performance. SUPPORT: WVU Office of Academic Affairs Doctoral Student Research Support (AM); WVU Alumni Fund (AM); WVU Behavioral and Biomedical Sciences Training Scholarship Research Award (AM) EFFECTS OF A POSTPARTUM SLEEP SCHEDULE iii