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Association between maternal sleep practices and risk of late stillbirth: a case-control study

BMJ 2011; 342 doi: (Published 14 June 2011) Cite this as: BMJ 2011;342:d3403
  1. Tomasina Stacey, midwifery lecturer, PhD student1,
  2. John M D Thompson, senior research fellow2,
  3. Ed A Mitchell, professor of child health research2,
  4. Alec J Ekeroma, senior lecturer, obstetrics and gynaecology1,
  5. Jane M Zuccollo, senior lecturer, perinatal pathology3,
  6. Lesley M E McCowan, professor of obstetrics and gynaecology1
  1. 1Department of Obstetrics and Gynaecology, University of Auckland, Private Bag 92019 Auckland 1142, New Zealand
  2. 2Department of Paediatrics, University of Auckland, Auckland
  3. 3Department of Obstetrics and Gynaecology, Wellington Medical School, Wellington 6021, New Zealand
  1. Correspondence to: T Stacey t.stacey{at}
  • Accepted 17 May 2011


Objectives To determine whether snoring, sleep position, and other sleep practices in pregnant women are associated with risk of late stillbirth.

Design Prospective population based case-control study.

Setting Auckland, New Zealand

Participants Cases: 155 women with a singleton late stillbirth (≥28 weeks’ gestation) without congenital abnormality born between July 2006 and June 2009 and booked to deliver in Auckland. Controls: 310 women with single ongoing pregnancies and gestation matched to that at which the stillbirth occurred. Multivariable logistic regression adjusted for known confounding factors.

Main outcome measure Maternal snoring, daytime sleepiness (measured with the Epworth sleepiness scale), and sleep position at the time of going to sleep and on waking (left side, right side, back, and other).

Results The prevalence of late stillbirth in this study was 3.09/1000 births. No relation was found between snoring or daytime sleepiness and risk of late stillbirth. However, women who slept on their back or on their right side on the previous night (before stillbirth or interview) were more likely to experience a late stillbirth compared with women who slept on their left side (adjusted odds ratio for back sleeping 2.54 (95% CI 1.04 to 6.18), and for right side sleeping 1.74 (0.98 to 3.01)). The absolute risk of late stillbirth for women who went to sleep on their left was 1.96/1000 and was 3.93/1000 for women who did not go to sleep on their left. Women who got up to go to the toilet once or less on the last night were more likely to experience a late stillbirth compared with women who got up more frequently (adjusted odds ratio 2.28 (1.40 to 3.71)). Women who regularly slept during the day in the previous month were also more likely to experience a late stillbirth than those who did not (2.04 (1.26 to 3.27)).

Conclusions This is the first study to report maternal sleep related practices as risk factors for stillbirth, and these findings require urgent confirmation in further studies.


  • Contribution: TS participated in the design and coordination of the study, carried out the data collection, and drafted the manuscript. JMDT participated in the study design and assisted with statistical analysis and drafting the manuscript. EAM participated in the conception and design of the study, advised on the statistical analysis, and helped draft the manuscript. AJE participated in the design of the study and helped edit the manuscript. JMZ participated in the design of the study and helped to edit the manuscript. LMEM participated in the conception and design of the study and helped to draft the manuscript.

  • Funding: Funding received from: Cure Kids, the Nurture Foundation, and the Auckland District Health Board Trust fund. EAM, JMDT, and TS are supported in part by Cure Kids. The authors were independent of the funders in all aspects of study design, data analysis, and writing of the manuscript.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at (available on request from the corresponding author) and declare: TS, JMDT, and EAM received support from Cure Kids for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: The Northern X Regional Ethical Committee approved the study in June 2006 (NTX/06/05/054).

  • Data sharing: No additional data available.

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