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Am J Perinatol 2019; 36(01): 027-033
DOI: 10.1055/s-0038-1639356
SMFM Fellowship Series Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Risk Factors for Neonatal Hypoxic-Ischemic Encephalopathy in the Absence of Sentinel Events

Authors

  • Christopher M. Novak

    1   Division of Maternal-Fetal Medicine, Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, Maryland

  • Ahize C. Eke

    1   Division of Maternal-Fetal Medicine, Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, Maryland

  • Maide Ozen

    2   Division of Neonatal-Perinatal Medicine, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland
    3   Integrated Research Center for Fetal Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland

  • Irina Burd

    1   Division of Maternal-Fetal Medicine, Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, Maryland
    3   Integrated Research Center for Fetal Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
    4   Neuroscience Intensive Care Nursery Program, Johns Hopkins University School of Medicine, Baltimore, Maryland
    5   Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland

  • Ernest M. Graham

    1   Division of Maternal-Fetal Medicine, Department of Gynecology and Obstetrics, Johns Hopkins University School of Medicine, Baltimore, Maryland
    4   Neuroscience Intensive Care Nursery Program, Johns Hopkins University School of Medicine, Baltimore, Maryland

Funding E.M.G. is supported by NICHD grant R01HD086058.
Further Information

Publication History

13 October 2017

12 February 2018

Publication Date:
26 March 2018 (online)

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Abstract

Objective Hypoxic-ischemic encephalopathy (HIE) may be associated with intrapartum sentinel events or may be unexplained. We sought to identify risk factors for unexplained HIE cases and compare their morbidity and mortality to cases associated with sentinel events.

Study Design Retrospective cohort study of all neonates admitted with suspected HIE treated with whole-body hypothermia from January 2007 through July 2017. Cases of unexplained HIE were compared with those with a sentinel event.

Results A total of 223 neonates met the inclusion criteria, of which 86 (38.6%) experienced a sentinel event and 137 (61.4%) did not. Placental histopathology was performed for 28/31 (90.3%) and 48/53 (90.6%) inborn neonates with and without sentinel events, respectively. Placentas from unexplained HIE cases more often exhibited histologic chorioamnionitis (43.8% vs. 17.9%, p = 0.02) and funisitis (25% vs. 3.6%, p = 0.02). Neonatal morbidity and mortality were similar. On multivariable regression, nulliparity (odds ratio [OR], 4.11, 95% confidence interval [CI]: 1.24–13.62) and histologic funisitis (OR, 20.33, 95% CI: 1.11–373.4) remained significant.

Conclusion Other than nulliparity and infection which could be identified on umbilical cord examination following delivery but not on clinical assessment prior to delivery, there are no other identifiable risk factors for HIE in the absence of a sentinel event, and morbidity and mortality are similar between groups.

Keywords

hypoxic-ischemic encephalopathy - histologic funisitis - neonatal metabolic acidosis - sentinel events