conclusions

resultsbackground

method

Participants

In the postpartum period these mothers experienced disrupted sleep at night, mainly due to the care of their infant, and some mothers did not obtain more than 4.5 hours of continuous sleep during the early weeks.The level of sleep disruption varied greatly between the mothers, suggesting notable individual differences.As indicated by the total number of driving episodes undertaken, there was notable exposure to the road environment in this sample, which included a large proportion (86%) indicating 7 or more driving episodes during the 7-day assessment weeks. Over half of the driving episodes during week 6 were undertaken with a sleepiness rating linked with elevated crash risk. Qualitative data suggested that some mothers employed self-regulated driving behaviour, however a reliance on driving appeared to lead to some mothers driving despite awareness of their elevated sleepiness levels. At 12 weeks postpartum, compared to 6 weeks, many mothers experienced less disrupted sleep and longer continuous sleep periods. Also, the number of driving episodes undertaken increased for many mothers. Taken together, it is positive to note that the percentage of driving episodes with a KSS of 5 or above decreased.

Previous studies investigating mothers’ sleep in the postpartum period commonly demonstrated elevated levels of sleepiness in this population1,2.

At 4 weeks postpartum, many mothers report their infants wake three or more times between 22:00 and 06:003.

Sleepiness and fatigue-related vehicle crashes are prevalent, even though sleepiness symptoms are easily recognisable4.

A Karolinska Sleepiness Scale (KSS) rating of 5 or above is associated with an exponential increase in vehicle crash risk5.

To date, limited studies have investigated the relationship between mothers’ sleep in the postpartum period and their driving behaviour.

The mothers obtained significantly less sleep than the infants during week 6 (t(24) = -8.26, p <.001), as well as during week 12 (t(24) = -12.42, p <.001).

Mothers and infants experienced similar numbers of night awakenings (waking between 22:00 and 06:00) during week 6 (t(24) = -.09, ns), as well as week 12 (t(24) = .18, ns).

Number of night awakenings were lower during week 12 than week 6 for over two-thirds of the mothers.Notable individual differences were observed with mothers’ night awakenings during week 6 (Range = 3 to 20) as well as week 12 (Range = 2 to 24). During week 6, 36% of the mothers did not experience a sleep period longer than 4.5 hours. Maximum sleep periods were longer during week 12 than week 6 in 75% of mothers.

Mothers’ Sleep and Driving in the Postpartum PeriodJanelle Trenorden, Kerry Armstrong & Simon SmithCentre for Accident Research and Road Safety - Queensland, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia

Mean age = 29.79 years (SD = 3.7 years).All were married, had a partner or were in a de facto relationship.

Materials

Procedure

14 mothers who gave birth between April & September 2011.

7-day sleep-wake diary completed at 6 and 12 weeks postpartum.

7-day sleep-wake diary, indicating:

During week 6, 10 mothers were solely breastfeeding and 4 mothers were combining breast and bottle-feeding.

− all sleep periods for mother;− all sleep periods for baby;− mother’s driving episodes and KSS rating.

Sleep characteristics

Driving characteristicsIn total there were 141 driving episodes

undertaken during week 6, which rose to 175 episodes during week 12.

Strategies used to self-regulate drivingStrategies cited included:

Figure 1. Percentage of driving episodes by KSS annotation for Week 6 (N = 137) and Week 12 (N = 175)

KSS rating

Perc

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(%)

Semi-structured telephone interviews were undertaken which helped mothers share their thoughts and experiences of sleepiness since giving birth to their baby.

Semi-structured telephone interview completed at 12 weeks postpartum.

− only driving when feeling alert; − driving in the morning when less sleepy; and− postponing driving until another person is

present.

References:1. Carty, E., Bradley, C., & Winslow, W. (1996). Women’s perceptions of fatigue during pregnancy and postpartum: The impact of length and hospital stay, Clinical Nursing Research, 5(1), 67-80. doi: 10.1177/1054773896005001062. Meltzer, L. & Mindell, J. (2007). Relationship between child sleep disturbances and maternal sleep, mood, and parenting stress: A pilot study. Journal of Family Psychology, 21(1), 67-73. doi: 10.1037/0893-3200.21.1.673. Dennis, C. & Ross, L. (2005). Relationships among infant sleep patterns, maternal fatigue, and development of depressive symptomatology, Birth, 32(3), 187-193. 10.1111/j.0730-7659.2005.00368.x4. Akerstedt, T. (2000). Consensus Statement: Fatigue and accidents in transport operations. Journal of Sleep Research, 9(4), 395. doi: 10.1046/j.1365-2869.2000.00228.x5. Akerstedt, T., Connor, J., Gray, A., & Kecklund, G. (2008). Predicting road crashes from a mathematical model of alertness regulation – The Sleep/Wake Predictor. Accident, Analysis & Prevention, 40, 1480-1485. doi: 10.1016/j.aap.2008.03.016

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30 Week 6

Week 12

Increased crash risk

During week 6, 51.8% of the episodes were undertaken with a KSS of 5 or more, which reduced to 32.2% during week 12 (see Fig. 1).