title: Association between maternal sleep practices and risk of late stillbirth: a case-control study.
abstract: OBJECTIVE
  To determine whether snoring, sleep position, and other sleep practices in pregnant women are associated with risk of late stillbirth.
  
  
  METHODS
  Prospective population based case-control study.
  
  
  METHODS
  Auckland, New Zealand
  
  
  METHODS
  
  
  
  METHODS
  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.
  
  
  METHODS
  310 women with single ongoing pregnancies and gestation matched to that at which the stillbirth occurred. Multivariable logistic regression adjusted for known confounding factors.
  
  
  METHODS
  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.
authors.affiliation: Department of Obstetrics and Gynaecology, University of Auckland, Private Bag 92019 Auckland 1142, New Zealand. t.stacey@auckland.ac.nz
authors.forename: Tomasina
authors.initials: T
authors.lastname: Stacey
authors.forename: John M D
authors.initials: JM
authors.lastname: Thompson
authors.forename: Ed A
authors.initials: EA
authors.lastname: Mitchell
authors.forename: Alec J
authors.initials: AJ
authors.lastname: Ekeroma
authors.forename: Jane M
authors.initials: JM
authors.lastname: Zuccollo
authors.forename: Lesley M E
authors.initials: LM
authors.lastname: McCowan
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D009520:New Zealand / Q000453:epidemiology; D011247:Pregnancy / Q000502:physiology*; D011446:Prospective Studies; D012307:Risk Factors; D012890:Sleep; D050497:Stillbirth