Effects of a single night of postpartum sleep on childless women's daytime functioning

Abstract

Study objectives: The maternal postpartum period is characterized by sleep fragmentation, which is associated with daytime impairment, mental health disturbances, and changes in melatonin patterns. In addition to sleep fragmentation, women undergo a complex set of physiological and environmental changes upon entering the postpartum period, confounding our understanding of effects of postpartum sleep disturbance. The primary study aim was to understand the basic impact of a single night of postpartum-like sleep fragmentation on sleep architecture, nocturnal melatonin levels, mood, daytime sleepiness, and neurobehavioral performance.

Measurements and results: For one week prior to entry into the laboratory, eleven healthy nulliparous women kept a stable sleep-wake schedule (verified via actigraphy). Participants contributed three consecutive nights of laboratory overnight polysomnography: (1) a habituation/sleep disorder screening night; (2) a baseline night; and (3) a sleep fragmentation night, when participants were awakened three times for ~30min each. Self-reported sleep quality and mood (Profile of Mood States survey) both decreased significantly after sleep fragmentation compared to baseline measurements. Unexpectedly, daytime sleepiness (Multiple Sleep Latency Test) decreased significantly after sleep fragmentation. Experimental fragmentation had no significant effect on time spent in nocturnal sleep stages, urinary 6-sulfatoxymelatonin concentration, or psychomotor vigilance test performance. Participants continued to provide actigraphy data, and daily PVTs and self-reported sleep quality assessments at home for one week following sleep fragmentation; these assessments did not differ from baseline values.

Conclusions: While there were no changes in measured physiological components of a single night of postpartum-like experimental sleep fragmentation, there were decreases in self-reported measures of mood and sleep quality. Future research should examine the effects of multiple nights of modeling postpartum-like sleep fragmentation on objective measures of sleep and daytime functioning.

Keywords: Daytime sleepiness; Maternal; Mood; Polysomnography; Sleep fragmentation; Sleep quality.

Figure 1

Study protocol for a participant with a habitual sleep period from 12–8am

Figure 2. Participant inclusion and exclusion throughout the study

*Were unable to participate due to scheduling difficulties or were no longer interested after the details of the study were described. #Reasons for ineligibility to begin study: on antidepressant medication (n=1), symptoms of a sleep disorder (n=2), major medical condition (n=1). ^Reasons for ineligibility to continue study: sleep/wake times differed across baseline week by >3 hr (n=1), scored <8 min on baseline MSLT (n=4), sleep disorder symptoms on screening night (n=1).

Figure 3. Self-reported sleep quality the morning after baseline and sleep fragmentation nights, and across the post-fragmentation week (Error bars represent SE; **=p<.01)

Base = Baseline polysomnography night in the lab; Frag = Experimental sleep fragmentation night.

Figure 4

POMS TMD scores during baseline and days after sleep fragmentation (Error bars represent SE; *=p<.05).

Figure 5

POMS subscale scores at baseline and the day after sleep fragmentation (Error bars represent SE; ***p<.001).

Figure 6

MSLT sleep onset latencies for individual nap opportunities between baseline and the day after experimental sleep fragmentation (Error bars represent SE; **=p<.01)