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Prospective Evaluation of Maternal Sleep Position Through 30 Weeks of Gestation and Adverse Pregnancy Outcomes

Silver, Robert M. MD; Hunter, Shannon MS; Reddy, Uma M. MD, MPH; Facco, Francesca MD; Gibbins, Karen J. MD; Grobman, William A. MD, MBA; Mercer, Brian M. MD; Haas, David M. MD, MS; Simhan, Hyagriv N. MD; Parry, Samuel MD; Wapner, Ronald J. MD; Louis, Judette MD; Chung, Judith M. MD; Pien, Grace MD; Schubert, Frank P. MD; Saade, George R. MD; Zee, Phyllis MD; Redline, Susan MD; Parker, Corette B. DrPH for the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be (NuMoM2b) Study

doi: 10.1097/AOG.0000000000003458
Obstetrics: Original Research: PDF Only

OBJECTIVE: To examine the relationship between prospectively assessed maternal sleep position and subsequent adverse pregnancy outcomes.

METHODS: This was a secondary analysis of a prospective observational multicenter cohort study of nulliparous women with singleton gestations who were enrolled between October 2010 and May 2014. Participants had three study visits that were not part of clinical care. They prospectively completed in-depth sleep questionnaires between 6 0/7 and 13 6/7 weeks of gestation and 22 0/7 and 29 6/7 weeks of gestation, the first and third study visits. A subset of women also underwent level 3 home sleep tests using the Embletta Gold device. The primary outcome was a composite of adverse pregnancy outcomes such as stillbirth, a small-for-gestational-age newborn, and gestational hypertensive disorders.

RESULTS: A total of 8,706 (of 10,038) women had data from at least one sleep questionnaire and for pregnancy outcomes, and they comprised the population for this analysis. The primary outcome occurred in 1,903 pregnancies (22%). There was no association between reported non–left lateral or supine sleep during the last week of the first visit (adjusted odds ratio [aOR] 1.00 [95% CI 0.89–1.14]) or third visit (aOR 0.99 [95% CI 0.89–1.11] and the composite or any individual outcome, except for an apparent protective effect for stillbirth at the third visit (aOR 0.27 (95% CI 0.09–0.75). Women with objectively measured supine sleep position for at least 50% of the time were no more likely than those in the supine position 50% or less of the time to have the composite adverse outcome.

CONCLUSIONS: Going to sleep in the supine or right lateral position, as self-reported before the development of pregnancy outcome and objectively assessed through 30 weeks of gestation, was not associated with an increased risk of stillbirth, a small-for-gestational-age newborn, or gestational hypertensive disorders.

Going to sleep in the supine or right lateral position through 30 weeks of gestation was not associated with adverse pregnancy outcomes.

University of Utah, Salt Lake City, Utah; RTI International, Research Triangle Park, North Carolina; Yale University, New Haven, Connecticut; University of Pittsburgh, Pittsburgh, Pennsylvania; Oregon Health & Science University, Portland, Oregon; Northwestern University, Evanston, Illinois; Case Western Reserve University, Cleveland, Ohio; Indiana University, Bloomington, Indiana; University of Pennsylvania, Philadelphia, Pennsylvania; Columbia University, New York, New York; University of South Florida, Tampa, Florida; University of California–Irvine, Irvine, California; Johns Hopkins Medicine, Baltimore, Maryland; University of Texas Medical Branch at Galveston, Galveston, Texas; and Brigham and Women's Hospital, Boston, Massachusetts.

Corresponding author: Robert M. Silver, MD, Department of Obstetrics and Gynecology, University of Utah School of Medicine, Salt Lake City, UT; email:

Supported by grant funding from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD): U10 HD063036, RTI International; U10 HD063072, Case Western Reserve University; U10 HD063047, Columbia University; U10 HD063037, Indiana University; U10 HD063041, University of Pittsburgh; U10 HD063020, Northwestern University; U10 HD063046, University of California Irvine; U10 HD063048, University of Pennsylvania; and U10 HD063053, University of Utah. In addition, support was provided by respective Clinical and Translational Science Institutes to Indiana University (UL1TR001108) and University of California Irvine (UL1TR000153).

Financial Disclosure Judette Louis reports receiving research funds paid to her institution by Kyndermed. Grace Pien reports receiving royalties from The other authors did not report any potential conflicts of interest.

Presented in part at the 39th Annual Meeting of the Society for Maternal-Fetal Medicine, February 11–16, 2019, Dallas, Texas.

The authors thank the study coordinators for their tireless efforts in compiling these data and participants in the cohort.

Each author has confirmed compliance with the journal's requirements for authorship.

Peer reviews and author correspondence are available at

Received March 25, 2019

Received in revised form May 31, 2019

Accepted June 13, 2019

© 2019 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.