Seeking order amidst chaos : a systematic review of classification systems for causes of stillbirth and neonatal death, 2009-2014
Leisher, Susannah Hopkins; Teoh, Zheyi; Reinebrant, Hanna; Allanson, Emma; Blencowe, Hannah; Frøen, J. Frederik; Gardosi, Jason; Gordijn, Sanne; Gulmezoglu, A. Metin; Heazell, Alexander E. P.; Korteweg, Fleurisca; Lawn, Joy; McClure, Elizabeth M.; Pattinson, Robert Clive; Smith, Gordon C. S.; Tuncalp, Ozge; Wojcieszek, Aleena M.; Flenady, Vicki
BACKGROUND : 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
METHODS : 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published and unpublished studies and national reports describing new classification systems or modifications of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.
RESULTS : 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.
CONCLUSIONS : 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
Additional file 1: PRISMA checklist.
Additional file 2: Decision tree for inclusion/exclusion.
Additional file 3: List of variables extracted.
Additional file 4: Sensitivity of number of “widely used” systems to cut-offs
for number of countries in which used and number of deaths classified.
Additional file 5: All included publications with reason for inclusion and
Additional file 6: Year of creation/modification of classification systems
for causes of stillbirth and neonatal death developed or used between 2009
Additional file 7: Countries in which more than one system was used
to classify causes of stillbirths and/or neonatal deaths, 2009-2014.
Additional file 8: National classification systems for causes of stillbirth and
neonatal death in use 2009-2014.
Additional file 9: Classification systems for causes of stillbirth and
neonatal death used in highest-burden countries, 2009-2014.
Additional file 10: Maximum percent of deaths classified as “other” and
“unexplained” by classification systems according to type of death
Additional file 11: Kappa scores from reliability testing of classification
systems for causes of stillbirth and neonatal death in use 2009-2014.
Additional file 12: Selected shortcomings of existing systems and
rationale for development of new systems/modification of existing