Hush-a-by mummy: interactions between co-sleeping and
maternal sleep disturbance
Ashleigh Filtness*, Janelle Mackenzie, Kerry Armstrong
CARRS-Q, Queensland University of Technology, Queensland, Australia
*ashleigh.filtness@qut.edu.au
Summary:
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In relation to other sub-populations vulnerable to sleep loss (e.g. shift workers) sleep in new mothers is comparably under investigated.
At postpartum weeks 6, 12 and 18 the quantity of sleep new mothers obtain is consistent (≈7h), as are the frequency of night time wakings.
Sleep disturbance reduces over time, as the duration of time awake per night time waking reduces.
Mothers co-sleeping with their infant reported greater disturbance to their sleep and great ESS during weeks 6 and 12 than those who did
not co-sleep, these differences are not apparent by week 18.
Introduction
Childbirth is an extraordinary, everyday experience; in 2011, 301 617
infants were born in Australia [1], resulting in countless potential
occurrences of sleep disturbance and subsequent daytime sleepiness.
While the relationship between sleep and sleepiness has been heavily
investigated in the vulnerable sub-populations of shift workers and
patients with sleep disorders, comparatively postpartum women have
been overlooked.
Previous research has reported slower reaction times to the
Psychomotor Vigilance Task [2] and shorter sleep onset in the multiple
sleep latency test [3] in new mothers compared with control women.
However little is known about change in sleep and sleepiness over time
or potential interactions with infant care behaviour choices, such as cosleeping (mother and infant sharing a bed).
This study aims to investigate change in new mothers sleep quantity,
sleep quality and resulting daytime sleepiness over postpartum weeks
6, 12 and 18, while evaluating the impact of co-sleeping.
Method
Participants: Thirty three new mothers, mean age 30.0 years (SD 4.0) free from
psychiatric or medical problems, including postpartum depression.
Protocol: Participants prospectively recorded every episode of sleep and wake
(themselves and their infant) including sleep location during the 168 hours of
postpartum weeks 6, 12 and 18, in 15 minute epochs. Participants chose their own
sleeping arrangements. Nocturnal sleep period was considered to be made up of
recurrent sleep episodes whereby any intermittent wake periods were shorter than
the subsequent sleep episode.
Sleep measures: Total nocturnal sleep time (TST), number of nocturnal wake
episodes, sleep disturbance index (SDI; = (WASO / nocturnal sleep period)*100).
Sleepiness measures: Subjective sleepiness was reported using the Epworth
Sleepiness Scale (ESS), completed once per study week.
Analysis: Data for all measures were analysed using mixed measures ANOVA with
the within-subjects factors of Time (3 levels: week 6, week 12, and week 18) and
the between subjects factors of Group (2 levels: no co-sleeping and co-sleeping).
Post-hoc pairwise comparisons were conducted using Bonferroni tests
Results
Figure 1: Epworth sleepiness score with standard error bars
Epworth Sleepiness Scale
There was a significant group by time interaction
[F(2,62)=10.04, p< 0.001], daytime sleepiness
being greater for co-sleepers (n =6) during weeks
6 and 12. Overall, ESS reduced over time
[F(2,62)=30.07, p< 0.001].
Figure 2: Night time sleep (left axis) and number of wakings (right axis)
with standard error bars
Figure 3: Sleep disturbance index with standard error bars
Night time sleep
Number of minutes sleep obtained did not change
across time points [F(2,62)=0.19, p = 0.824] nor
did number of night time wakings [F(2,62)= 1.02,
p = 0.366]. There was no interacting effect of cosleeping.
Sleep disturbance index
There was a significant group by time interaction
[F(2,54.51)=3.73, p = 0.035], sleep disturbance
being greater for co-sleepers (n = 6) during weeks
6 and 12. Overall, SDI reduced over time
[F(2,54.51)=18.82 p< 0.001].
Conclusion
Daytime sleepiness in new mothers can reach clinically dangerous levels. Excessive daytime sleepiness (EDS; ESS >12) was common; 66.7% of participants in
week 6 and 60.6% of participants in week 12. A clinician faced with a patient with an 18 week history of EDS would likely offer advice and information
regarding implications for daytime impairment (e.g. when driving), yet little is known about the implications for EDS in otherwise healthy postpartum women.
Considering that sleep quantity and frequency of night time wakings remained consistent, daytime sleepiness appears to be driven by the duration of the sleep
disturbances. The reduction of SDI and consistent number of wakings over time suggest improved efficiency by mothers at settling their infant back to sleep.
Although ESS and SDI decreased over time the reduction occurred earlier for those choosing not to co-sleep, demonstrating the impact of infant care choices.
Participants dictated their own sleeping arrangement; the majority of mothers choose not to co-sleep. Consequently, current results should be considered
preliminary. Future research with postpartum mothers may wish to consider a recruitment strategy based on intentions to co-sleep or not.
These results are important as they quantify the excessive level of sleepiness experienced by the new mothers. Healthcare providers advising new mothers
should consider the potential influence of co-sleeping on the dynamic changes to sleep and sleepiness during the initial postpartum period.
References:
[1] Australian Bureau of Statistics (2011) "Births, Summary statistics for Australia." Accessed 1/7/13.
[2] Insana, Salvatore P, Kayla B Williams and Hawley E Montgomery-Downs. 2013. "Sleep disturbance and neurobehavioral performance among postpartum women." Sleep 36 (1): 73-81.
[3] Insana, Salvatore P and Hawley E Montgomery‐Downs. 2012. "Sleep and sleepiness among first‐time postpartum parents: A field‐and laboratory‐based multimethod assessment."
Developmental Psychobiology.
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CRICOS No. 00213J