Abstract
Background
Extremely preterm infants (EPT, <29 weeks’ gestation) represent only 0.9% of births in the United States; yet these infants are the focus of most published research. Moderately preterm neonates (MPT, 29–336/7 weeks) are an understudied group of high-risk infants.
Methods
To determine the neonatal outcomes of MPT infants across the gestational age spectrum, and to compare these with EPT infants. A prospective observational cohort was formed in 18 level 3–4 neonatal intensive care units (NICUs) in the Eunice Kennedy Shriver NICHD Neonatal Research Network. Participants included all MPT infants admitted to NICUs and all EPT infants born at sites between January 2012 and November 2013. Antenatal characteristics and neonatal morbidities were abstracted from records using pre-specified definitions by trained neonatal research nurses.
Results
MPT infants experienced morbidities similar to, although at lower rates than, those of EPT infants. The main cause of mortality was congenital malformation, accounting for 43% of deaths. Central Nervous System injury occurred, including intraventricular hemorrhage. Most MPT infants required respiratory support, but sequelae such as bronchopulmonary dysplasia were rare. The primary contributors to hospitalization beyond 36 weeks’ gestation were inability to achieve adequate oral intake and persistent apnea.
Conclusions
MPT infants experience morbidity and prolonged hospitalization. Such morbidity deserves focused research to improve therapeutic and prevention strategies.
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Acknowledgements
Funding Sources: The National Institutes of Health, the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), and the National Center for Advancing Translational Sciences provided grant support for the Neonatal Research Network’s Moderately Preterm Registry through cooperative agreements. Although NICHD staff did have input into the study design, conduct, analysis, and manuscript drafting, the content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Author contributions
The contributions made by each author for this manuscript are given in detail below.
The MPR Subcommittee investigators have monthly conference calls, during which protocol design and implementation issues are discussed, manuscripts are reviewed, and input obtained. The following authors have made significant contributions as determined by the Uniform Requirements for Manuscripts Submitted to Biomedical Journals:
Michele C. Walsh, MD, MS, is the Lead Principal Investigator (PI) at Case Western Reserve University (CWRU) and the Chair of the Moderately Preterm Registry Protocol Subcommittee. She developed the study and managed protocol implementation. As the PI at CWRU, she oversaw enrollment at the site—which enrolled 302 infants in this study. Walsh drafted the manuscript and received input from the authors below as part of manuscript revision. Walsh had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Edward F. Bell, MD, is the PI at the University of Iowa and a member of the Moderately Preterm Registry Protocol Subcommittee. He helped develop the study and manage protocol implementation. As the PI at the University of Iowa, he oversaw enrollment at the site—which enrolled 495 infants in this study. He contributed critical revisions of the manuscript and approved the final manuscript for submission.
Sarah Kandefer, BS, served as the primary statistician for the study, and completed the statistical analyses for the paper. She developed the tables for the paper and provided critical revision to the manuscript and approved the final version of the manuscript.
Waldemar A. Carlo, MD, is the PI at the University of Alabama at Birmingham (UAB) and a member of the Moderately Preterm Registry Protocol Subcommittee. He helped develop the study and manage protocol implementation. As the PI at UAB, he oversaw enrollment at the site—which enrolled 537 infants in this study. He contributed critical revisions of the manuscript and approved the final manuscript for submission.
Carl T. D’Angio, MD, is the PI at the University of Rochester and a member of the Moderately Preterm Registry Protocol Subcommittee. He helped develop the study and manage protocol implementation. As the PI at the University of Rochester, he oversaw enrollment at the site—which enrolled 617 infants in this study. He contributed critical revisions of the manuscript and approved the final manuscript for submission.
Abbot R. Laptook, MD, is the PI at Brown University and a member of the Moderately Preterm Registry Protocol Subcommittee. He helped develop the study and manage protocol implementation. As the PI at Brown University, he oversaw enrollment at the site—which enrolled 424 infants in this study. He contributed critical revisions of the manuscript and approved the final manuscript for submission.
Pablo J. Sanchez, MD, is the PI at Nationwide Children’s Hospital and a member of the Moderately Preterm Registry Protocol Subcommittee. He helped develop the study and manage protocol implementation. As the PI at Nationwide Children’s Hospital, he oversaw enrollment at the site—which enrolled 512 infants in this study. He contributed critical revisions of the manuscript and approved the final manuscript for submission.
Barbara J. Stoll, MD, is the PI at Emory University and the Vice Chair of the Moderately Preterm Registry Protocol Subcommittee. She helped develop the study and manage protocol implementation. As the PI at Emory University, she oversaw enrollment at the site—which enrolled 335 infants in this study. She contributed critical revisions of the manuscript and approved the final manuscript for submission.
Seetha Shankaran, MD, is the PI at Wayne State University and a member of the Moderately Preterm Registry Protocol Subcommittee. She helped develop the study and manage protocol implementation. As the PI at Wayne State University, she oversaw enrollment at the site—which enrolled 363 infants in this study. She contributed critical revisions of the manuscript and approved the final manuscript for submission.
Krisa P. Van Meurs, MD, is the PI at Stanford University and a member of the Moderately Preterm Registry Protocol Subcommittee. She helped develop the study and manage protocol implementation. As the PI at Stanford University, she oversaw enrollment at the site—which enrolled 205 infants in this study. She contributed critical revisions of the manuscript and approved the final manuscript for submission.
Betty R. Vohr, MD, is the Follow-up PI at Brown University and a member of the Moderately Preterm Registry Protocol Subcommittee. She helped develop and implement the study and contributed critical revisions of the manuscript and approved the final manuscript for submission.
Rosemary D. Higgins, MD, served as the Program Scientist for the NICHD NRN and is a member of the Moderately Preterm Registry Protocol Subcommittee. Dr Higgins helped develop the protocol, oversaw recruitment, and assisted with data edits from the sites. She also provided critical revision to the manuscript and approved the final version of the manuscript.
Abhik Das, PhD, is the PI for the NRN Data Coordinating Center and a member of the Moderately Preterm Registry Protocol Subcommittee. Das oversaw all aspects of the statistical analysis, provided critical revisions to the manuscript, and approved the final version of the manuscript.
Ellen C. Hale, BS, RN, CCRC, is the Coordinator at Emory University and a member of the Moderately Preterm Registry Protocol Subcommittee. She helped develop the study and manage protocol implementation. As the Coordinator at Emory University, she enrolled 335 infants in this study. She contributed critical revisions of the manuscript and approved the final manuscript for submission.
Nancy S. Newman, RN, is the Coordinator at CWRU and a member of the Moderately Preterm Registry Protocol Subcommittee. She helped develop the study and manage protocol implementation. As the Coordinator at CWRU, she enrolled 302 infants in this study. She contributed critical revisions of the manuscript and approved the final manuscript for submission.
Kurt Schibler, MD, is the PI at Cincinnati Children’s Medical Center (CCMC). As the PI he oversaw enrollment at the site—which enrolled 683 infants in this study. He contributed critical revisions of the manuscript and approved the final manuscript for submission.
Barbara Schmidt, MD, is the PI at the University of Pennsylvania. As the PI she oversaw enrollment at the site—which enrolled 511 infants in this study. She contributed critical revisions of the manuscript and approved the final manuscript for submission.
C. Michael Cotten, MD, MHS, is the PI at Duke University. As the PI he oversaw enrollment at the site—which enrolled 457 infants in this study. He contributed critical revisions of the manuscript and approved the final manuscript for submission.
Kathleen A. Kennedy, MD, MPH, is the PI at the University of Texas Health Science Center at Houston. As the PI she oversaw enrollment at the site—which enrolled 456 infants in this study. She contributed critical revisions of the manuscript and approved the final manuscript for submission.
Brenda B. Poindexter, MD, MS, is the PI at Indiana University. As the PI, she oversaw enrollment at the site—which enrolled 333 infants in this study. She contributed critical revisions of the manuscript and approved the final manuscript for submission.
Kristi L. Watterberg, MD, is the PI at the University of New Mexico. As the PI, she oversaw enrollment at the site—which enrolled 242 infants in this study. She contributed critical revisions of the manuscript and approved the final manuscript for submission.
William E. Truog, MD, is the PI at Children's Mercy Hospital, Kansas City. As the PI, he oversaw enrollment at the site—which enrolled 172 infants in this study. He contributed critical revisions of the manuscript and approved the final manuscript for submission.
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Presentations: portions of the material in this manuscript were presented at the Pediatric Academic Society Meeting, May 2014, Vancouver, BC, Canada.
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Walsh, M., Bell, E., Kandefer, S. et al. Neonatal outcomes of moderately preterm infants compared to extremely preterm infants. Pediatr Res 82, 297–304 (2017). https://doi.org/10.1038/pr.2017.46
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DOI: https://doi.org/10.1038/pr.2017.46
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