Cronin, RobinLi, MinglanThompson, JohnGordon, AdrienneRaynes-Greenow, Camille HHeazell, Alexander EPStacey, TomasinaCulling, Vicki MBowring, VictoriaAnderson, NgaireO'Brien, Louise MMitchell, EdwinAskie, Lisa MMcCowan, Lesley2019-10-012019-04-02EClinicalMedicine 10:49-57 01 Apr 20192589-5370http://hdl.handle.net/2292/48249Background:Maternal supine going-to-sleep position has been associated with increased risk of late stillbirth (≥ 28 weeks), but it is unknown if the risk differs between right and left side, and if some pregnancies are more vulnerable. Methods:Systematic searches were undertaken for an individual-level participant data (IPD) meta-analysis of case-control studies, prospective cohort studies and randomised trials undertaken up until 26 Jan, 2018, that reported data on maternal going-to-sleep position and stillbirth. Participant inclusion criteria included gestation ≥ 28 weeks', non-anomalous, singleton pregnancies. The primary outcome was stillbirth. A one-stage approach stratified by study and site was used for the meta-analysis. The interaction between supine going-to-sleep position and fetal vulnerability was assessed by bi-variable regression. The multivariable model was adjusted for a priori confounders. Registration number: PROSPERO, CRD42017047703. Findings:Six case-control studies were identified, with data obtained from five (cases, n = 851; controls, n = 2257). No data was provided by a sixth study (cases, n = 100; controls, n = 200). Supine going-to-sleep position was associated with increased odds of late stillbirth (adjusted odds ratio [aOR] 2.63, 95% CI 1.72-4.04, p < 0.0001) compared with left side. Right side had similar odds to left (aOR 1.04, 95% CI 0.83-1.31, p = 0.75). There were no significant interactions between supine going-to-sleep position and assessed indicators of fetal vulnerability, including small-for-gestational-age infants (p = 0.32), maternal obesity (p = 0.08), and smoking (p = 0.86). The population attributable risk for supine going-to-sleep position was 5.8% (3.2-9.2). Interpretation:This IPD meta-analysis confirms that supine going-to-sleep position is independently associated with late stillbirth. Going-to-sleep on left or right side appears equally safe. No significant interactions with our assessed indicators of fetal vulnerability were identified, therefore, supine going-to-sleep position can be considered a contributing factor for late stillbirth in all pregnancies. This finding could reduce late stillbirth by 5.8% if every pregnant woman ≥ 28 weeks' gestation settled to sleep on her side.Electronic-eCollectionItems in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher.https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htmhttps://creativecommons.org/licenses/by-nc-nd/4.0/Journal Article10.1016/j.eclinm.2019.03.014Copyright: Elsevier Ltdhttp://purl.org/eprint/accessRights/OpenAccess2589-5370