title: Seeking order amidst chaos: a systematic review of classification systems for causes of stillbirth and neonatal death, 2009-2014.
abstract: Each year, about 5.3 million babies die in the perinatal period. Understanding of causes of death is critical for prevention, yet there is no globally acceptable classification system. Instead, many disparate systems have been developed and used. We aimed to identify all systems used or created between 2009 and 2014, with their key features, including extent of alignment with the International Classification of Diseases (ICD) and variation in features by region, to inform the World Health Organization's development of a new global approach to classifying perinatal deaths.
  
  
  
  A systematic literature review (CINAHL, EMBASE, Medline, Global Health, and PubMed) identified published and unpublished studies and national reports describing new classification systems or modifications of existing systems for causes of perinatal death, or that used or tested such systems, between 2009 and 2014. Studies reporting ICD use only were excluded. Data were independently double-extracted (except from non-English publications). Subgroup analyses explored variation by extent and region.
  
  
  
  Eighty-one systems were identified as new, modifications of existing systems, or having been used between 2009 and 2014, with an average of ten systems created/modified each year. Systems had widely varying characteristics: (i) comprehensiveness (40 systems classified both stillbirths and neonatal deaths); (ii) extent of use (systems were created in 28 countries and used in 40; 17 were created for national use; 27 were widely used); (iii) accessibility (three systems available in e-format); (iv) underlying cause of death (64 systems required a single cause of death); (v) reliability (10 systems tested for reliability, with overall Kappa scores ranging from .35-.93); and (vi) ICD alignment (17 systems used ICD codes). Regional databases were not searched, so system numbers may be underestimated. Some non-differential misclassification of systems was possible.
  
  
  
  The plethora of systems in use, and continuing system development, hamper international efforts to improve understanding of causes of death. Recognition of the features of currently used systems, combined with a better understanding of the drivers of continued system creation, may help the development of a truly effective global system.
authors.affiliation: Mater Research Institute, The University of Queensland (MRI-UQ), Brisbane, Australia. shl2164@cumc.columbia.edu.|International Stillbirth Alliance, Millburn, USA. shl2164@cumc.columbia.edu.
authors.forename: Susannah Hopkins
authors.initials: SH
authors.lastname: Leisher
authors.affiliation: Mater Research Institute, The University of Queensland (MRI-UQ), Brisbane, Australia.
authors.forename: Zheyi
authors.initials: Z
authors.lastname: Teoh
authors.affiliation: Mater Research Institute, The University of Queensland (MRI-UQ), Brisbane, Australia.|International Stillbirth Alliance, Millburn, USA.
authors.forename: Hanna
authors.initials: H
authors.lastname: Reinebrant
authors.affiliation: Department of Reproductive Health and Research including UNDP/UNFPA/UNICEF/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP), World Health Organization, Geneva, Switzerland.|School of Women's and Infants' Health, Faculty of Medicine, Dentistry and Health Sciences, University of Western Australia, Perth, Australia.
authors.forename: Emma
authors.initials: E
authors.lastname: Allanson
authors.affiliation: London School of Hygiene & Tropical Medicine, London, UK.
authors.forename: Hannah
authors.initials: H
authors.lastname: Blencowe
authors.affiliation: International Stillbirth Alliance, Millburn, USA.|The University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Jan Jaap
authors.initials: JJ
authors.lastname: Erwich
authors.affiliation: Department of International Public Health, Norwegian Institute of Public Health, Oslo, Norway.|Center for Intervention Science for Maternal and Child Health, University of Bergen, Bergen, Norway.
authors.forename: J Frederik
authors.initials: JF
authors.lastname: Frøen
authors.affiliation: Perinatal Institute, Birmingham, UK.
authors.forename: Jason
authors.initials: J
authors.lastname: Gardosi
authors.affiliation: International Stillbirth Alliance, Millburn, USA.|The University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Sanne
authors.initials: S
authors.lastname: Gordijn
authors.affiliation: Department of Reproductive Health and Research including UNDP/UNFPA/UNICEF/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP), World Health Organization, Geneva, Switzerland.
authors.forename: A Metin
authors.initials: AM
authors.lastname: Gülmezoglu
authors.affiliation: International Stillbirth Alliance, Millburn, USA.|Maternal and Fetal Health Research Centre, University of Manchester, Manchester, UK.|St. Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK.
authors.forename: Alexander E P
authors.initials: AE
authors.lastname: Heazell
authors.affiliation: International Stillbirth Alliance, Millburn, USA.|Department of Obstetrics and Gynaecology, Martini Hospital, Groningen, The Netherlands.
authors.forename: Fleurisca
authors.initials: F
authors.lastname: Korteweg
authors.affiliation: London School of Hygiene & Tropical Medicine, London, UK.
authors.forename: Joy
authors.initials: J
authors.lastname: Lawn
authors.affiliation: International Stillbirth Alliance, Millburn, USA.|Research Triangle Institute, North Carolina, USA.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: McClure
authors.affiliation: South Africa Medical Research Council Maternal and Infant Health Care Strategies Unit, University of Pretoria, Pretoria, South Africa.
authors.forename: Robert
authors.initials: R
authors.lastname: Pattinson
authors.affiliation: NIHR Biomedical Research Centre & Department of Obstetrics & Gynaecology, Cambridge University, Cambridge, UK.
authors.forename: Gordon C S
authors.initials: GC
authors.lastname: Smith
authors.affiliation: Department of Reproductive Health and Research including UNDP/UNFPA/UNICEF/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP), World Health Organization, Geneva, Switzerland.
authors.forename: Ӧzge
authors.initials: Ӧ
authors.lastname: Tunçalp
authors.affiliation: Mater Research Institute, The University of Queensland (MRI-UQ), Brisbane, Australia.|International Stillbirth Alliance, Millburn, USA.
authors.forename: Aleena M
authors.initials: AM
authors.lastname: Wojcieszek
authors.affiliation: Mater Research Institute, The University of Queensland (MRI-UQ), Brisbane, Australia.|International Stillbirth Alliance, Millburn, USA.
authors.forename: Vicki
authors.initials: V
authors.lastname: Flenady
mesh_terms: D002423:Cause of Death; D002965:Classification / Q000379:methods*; D005260:Female; D014943:Global Health / Q000145:classification*; D006801:Humans; D007231:Infant, Newborn; D038801:International Classification of Diseases; D008297:Male; D066087:Perinatal Death / Q000209:etiology*; D011247:Pregnancy; D015203:Reproducibility of Results; D050497:Stillbirth / Q000453:epidemiology*
keywords: Cause of death; Classification; Classification system; Neonatal death; Perinatal death; Stillbirth