Differences in perinatal and infant mortality in high-income countries: artifacts of birth registration or evidence of true differences?

BMC Pediatrics

K. S. Joseph⁷  Michael S. Kramer⁵  Reg S. Sauve²  Prakesh S. Shah³  Xun Zhang⁵  Stein Emil Vollset⁸  Rolv Skjærven⁸  Laust H. Mortensen⁹  Mika Gissler⁶  Ragnheiður I. Bjarnadóttir⁴  Anne-Marie Nybo Andersen⁹  Jocelyn Rouleau¹  Nicolas L. Gilbert¹  Juan Andrés León¹  Paromita Deb-Rinker¹ 

[1] Maternal and Infant Health Section, Surveillance and Epidemiology Division, Centre for Chronic Disease Prevention, Public Health Agency of Canada, 785 Carling Avenue, AL 6804A, Ottawa K1A 0K9, Ontario, Canada;Departments of Pediatrics and Community Health Sciences, University of Calgary, Calgary, Alberta, Canada;Department of Paediatrics, University of Toronto, Mount Sinai Hospital, Toronto, Ontario, Canada;Department of Obstetrics and Gynecology, Landspitali, Rekjavik, Iceland;Departments of Pediatrics and of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada;National Institute of Health and Welfare (THL), Helsinki, Finland;Department of Obstetrics and Gynaecology and the School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada;Medical Birth Registry of Norway, University of Bergen, Bergen, Norway;Department of Public Health, University of Copenhagen, Copenhagen, Denmark

关键词: Neonatal mortality;    Stillbirths;    Birth weight;    Gestational age;    Infant mortality;    Birth registration;   

Others  :  1224628
DOI  :  10.1186/s12887-015-0430-8

 received in 2015-02-02, accepted in 2015-08-21,  发布年份 2015

【 摘 要 】

Background

Variation in birth registration criteria may compromise international comparisons of fetal and infant mortality. We examined the effect of birth registration practices on fetal and infant mortality rates to determine whether observed differences in perinatal and infant mortality rates were artifacts of birth registration or reflected true differences in health status.

Methods

A retrospective population-based cohort study was done using data from Canada, United States, Denmark, Finland, Iceland, Norway, and Sweden from 1995–2005. Main outcome measures included live births by gestational age and birth weight; gestational age—and birth weight-specific stillbirth rates; neonatal, post-neonatal, and cause-specific infant mortality.

Results

Proportion of live births <22 weeks varied substantially: Sweden (not reported), Iceland (0.00 %), Finland (0.001 %), Denmark (0.01 %), Norway (0.02 %), Canada (0.07 %) and United States (0.08 %). At 22–23 weeks, neonatal mortality rates were highest in Canada (892.2 per 1000 live births), Denmark (879.3) and Iceland (1000.0), moderately high in the United States (724.1), Finland (794.3) and Norway (739.0) and low in Sweden (561.2). Stillbirth:live birth ratios at 22–23 weeks were significantly lower in the United States (79.2 stillbirths per 100 live births) and Finland (90.8) than in Canada (112.1), Iceland (176.2) and Norway (173.9). Crude neonatal mortality rates were 83 % higher in Canada and 96 % higher in the United States than Finland. Neonatal mortality rates among live births ≥28 weeks were lower in Canada and United States compared with Finland. Post-neonatal mortality rates were higher in Canada and United States than in Nordic countries.

Conclusions

Live birth frequencies and stillbirth and neonatal mortality patterns at the borderline of viability are likely due to differences in birth registration practices, although true differences in maternal, fetal and infant health cannot be ruled out. This study emphasises the need for further standardisations, in order to enhance the relevance of international comparisons of infant mortality.

【 授权许可】

   
2015 Deb-Rinker et al.

【 参考文献 】

• [1]Sachs BP, Fretts RC, Gardner R, Hellerstein S, Wampler NS, Wise PH. The impact of extreme prematurity and congenital anomalies on the interpretation of international comparisons of infant mortality. Obstet Gynecol. 1995; 85(6):941-946.
• [2]Howell EM, Blondel B. International infant mortality rates: Bias from reporting differences. Am J Public Health. 1994; 84(5):850-852.
• [3]United nations Children’s fund. The state of the world’s children. Maternal and newborn health. UNICEF. 2009. NewYork, USA.
• [4]Health at a Glance 2011: OECD Indicators, OECD 2011, OECD Publishing. http://dx. doi.org/10.1787/health_glance-2011-en webcite
• [5]Kramer MS, Platt RW, Yang H, Haglund B, Cnattingius S, Bergsjo P. Registration artifacts in international comparisons of infant mortality. Paediatr Perinat Epidemiol. 2002; 16(1):16-22.
• [6]Joseph KS, Liu S, Rouleau J, Lisonkova S, Hutcheon JA, Sauve R, et al. Influence of definition based versus pragmatic birth registration on international comparisons of perinatal and infant mortality: Population based retrospective study. BMJ (Online). 2012;344(7847).
• [7]Mohangoo AD, Blondel B, Gissler M, Velebil P, Macfarlane A, Zeitlin J. International comparisons of fetal and neonatal mortality rates in high-income countries: Should exclusion thresholds be based on birth weight or gestational age? PLoS ONE 2013, 8(5)p. e64869
• [8]MacDorman M, Mathews T. Behind international rankings of infant mortality: How the United States compares with Europe. Int J Health Services. 2010; 40(4):577-588.
• [9]Arntzen A, Andersen AMN. Social determinants for infant mortality in the Nordic countries, 1980-2001. Scand J Public Health. 2004; 32(5):381-389.
• [10]Jørgensen T, Mortensen LH, Andersen AMN. Social inequality in fetal and perinatal mortality in the Nordic countries. Scand J Public Health. 2008; 36(6):635-649.
• [11]Hagberg B, Hagberg G, Zetterstrom R. Decreasing perinatal mortality--increase in cerebral palsy morbidity. Acta Paediatr Scand. 1989; 78(5):664-670.
• [12]Canadian perinatal health report. 8th ed. Minister of Public Works and Government Services, Canada; 2008.
• [13]Martin JA. United States vital statistics and the measurement of gestational age. Paediatr Perinat Epidemiol. 2007;21 Suppl 2:13–21.
• [14]Joseph KS, Huang L, Liu S, Ananth CV, Allen AC, Sauve R, Kramer MS. Reconciling the high rates of preterm and postterm birth in the United States. Obstet Gynecol. 2007; 109(4):813-822.
• [15]Qin C, Dietz PM, England LJ, Martin JA, Callaghan WM. Effects of different data-editing methods on trends in race-specific preterm delivery rates, United States, 1990-2002. Paediatr Perinat Epidemiol. 2007;21 Suppl 2:41–9.
• [16]Høgberg U, Larsson N. Early dating by ultrasound and perinatal outcome - A cohort study. Acta Obstet Gynecol Scand. 1997; 76(10):907-912.
• [17]Breslow NE, Day NE. Statistical methods in cancer research. volume I - the analysis of case-control studies. IARC Sci Publ. 1980; 32:5-338.
• [18]Kirby RS. International comparisons of perinatal indicators. Br Med J. 2012; 344:e477.
• [19]Sepkowitz S. International rankings of infant mortality and the United States’ vital statistics natality data collecting system: Failure and success. Int J Epidemiol. 1995; 24(3):583-588.
• [20]Fenton AC, Field DJ, Mason E, Clarke M. Attitudes to viability of preterm infants and their effect on figures for perinatal mortality. Br Med J. 1990; 300(6722):434-436.
• [21]Ehrenthal DB, Wingate MS, Kirby RS. Variation by state in outcomes classification for deliveries less than 500 g in the United States. Matern Child Health J. 2011; 15(1):42-48.
• [22]Cnattingius S, Villamor E, Johansson S, Edstedt Bonamy AK, Persson M, Wikström AK et al.. Maternal obesity and risk of preterm delivery. J Am Med Assoc. 2013; 309(22):2362-2370.
• [23]Wilcox A, Skjaerven R, Buekens P, Kiely J. Birth weight and perinatal mortality: A comparison of the United States and Norway. J Am Med Assoc. 1995; 273(9):709-711.
• [24]Papiernik E, Zeitlin J, Delmas D, Draper ES, Gadzinowski J, Künzel W et al.. Termination of pregnancy among very preterm births and its impact on very preterm mortality: Results from ten European population-based cohorts in the MOSAIC study. BJOG. 2008; 115(3):361-368.
• [25]Joseph KS, Kinniburgh B, Hutcheon JA, Mehrabadi A, Basso M, Davies C et al.. Determinants of increases in stillbirth rates from 2000 to 2010. CMAJ. 2013; 185(8):E345-E351.
• [26]Ananth CV. Menstrual versus clinical estimate of gestational age dating in the United States: Temporal trends and variability in indices of perinatal outcomes. Paediatr Perinat Epidemiol. 2007;21 Suppl 2:22–30.
• [27]Mathews TM, MacDorman MF. Infant mortality statistics from the 2005 period linked Birth/Infant death data set. National vital statistics reports; 2008 vol 57 (2): 1-28. Hyattsville, MD: National Center for Health Statistics