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The Collaborative IPD of Sleep and Stillbirth (Cribss): is maternal going-to-sleep position a risk factor for late stillbirth and does maternal sleep position interact with fetal vulnerability? An individual participant data meta-analysis study protocol
  1. Minglan Li1,
  2. John M D Thompson1,2,
  3. Robin S Cronin1,
  4. Adrienne Gordon3,4,
  5. Camille Raynes-Greenow5,
  6. Alexander E P Heazell6,7,
  7. Tomasina Stacey8,
  8. Vicki Culling9,
  9. Victoria Bowring10,
  10. Edwin A Mitchell2,
  11. Lesley M E McCowan1,
  12. Lisa Askie11
  1. 1 Department of Obstetrics and Gynaecology, University of Auckland, Auckland, New Zealand
  2. 2 Department of Paediatrics and Child Health, University of Auckland, Auckland, New Zealand
  3. 3 Department of Newborn Care, Royal Prince Alfred Hospital Women and Babies, Sydney, New South Wales, Australia
  4. 4 Charles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia
  5. 5 Sydney School of Public Health, The University of Sydney, Sydney, New South Wales, Australia
  6. 6 Division of Developmental Biomedicine, Faculty of Medical and Human Sciences, Maternal and Fetal Health Research Centre, University of Manchester, Manchester, UK
  7. 7 St. Mary’s Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
  8. 8 School of Healthcare, University of Leeds, Leeds, UK
  9. 9 Vicki Culling Associates, Auckland, New Zealand
  10. 10 Stillbirth Foundation, Annandale, New South Wales, Australia
  11. 11 National Health and Medical Research Council Clinical Trials Centre, University of Sydney, Camperdown, New South Wales, Australia
  1. Correspondence to Dr Minglan Li;{at}


Introduction Accumulating evidence has shown an association between maternal supine going-to-sleep position and stillbirth in late pregnancy. Advising women not to go-to-sleep on their back can potentially reduce late stillbirth rate by 9%. However, the association between maternal right-sided going-to-sleep position and stillbirth is inconsistent across studies. Furthermore, individual studies are underpowered to investigate interactions between maternal going-to-sleep position and fetal vulnerability, which is potentially important for producing clear and tailored public health messages on safe going-to-sleep position. We will use individual participant data (IPD) from existing studies to assess whether right-side and supine going-to-sleep positions are independent risk factors for late stillbirth and to test the interaction between going-to-sleep position and fetal vulnerability.

Methods and analysis An IPD meta-analysis approach will be used using the Cochrane Collaboration-endorsed methodology. We will identify case–control and prospective cohort studies and randomised trials which collected maternal going-to-sleep position data and pregnancy outcome data that included stillbirth. The primary outcome is stillbirth. A one stage procedure meta-analysis, stratified by study with adjustment of a priori confounders will be carried out.

Ethics and dissemination The IPD meta-analysis has obtained central ethics approval from the New Zealand Health and Disability Ethics Committee, ref: NTX/06/05/054/AM06. Individual studies should also have ethical approval from relevant local ethics committees. Interpretation of the results will be discussed with consumer representatives. Results of the study will be published in peer-reviewed journals and presented at international conferences.

PROSPERO registration number CRD42017047703.

  • stillbirth
  • sleep position
  • individual participant data meta-analysis
  • small for gestational age
  • fetal movement

This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See:

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  • Contributors ML, JMDT, RSC, AG, CR-G, AEPH, TS, EAM, LMEM and LA conceptualised the study. ML, JMDT, RSC, AG, CR-G, AEPH, TS, VC, VB, EAM, LMEM and LA have participated in study design and funding application. ML drafted the manuscript and appendix 2. RSC drafted appendix 1. LA, JMDT, RSC, AG, CR-G, AEPH, TS, EAM and LMEM critically revised the manuscript. ML, JMDT, RSC, AG, CR-G, AEPH, TS, VC, VB, EAM, LMEM and LA have read and approved submission of the final manuscript. LMEM is the guarantor of the review.

  • Funding This work was supported by 2016 Trans-Tasman Research Funding Grant by Cure Kids and Red Nose, Australia (Grant 6601).

  • Disclaimer Funder has no role in developing the protocol.

  • Competing interests None declared.

  • Patient consent Not required.

  • Ethics approval New Zealand Health and Disability Ethics Committee, ref: NTX/06/05/054/AM06.

  • Provenance and peer review Not commissioned; externally peer reviewed.