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Variations in very preterm birth rates in 30 high-income countries: are valid international comparisons possible using routine data?

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journal contribution
posted on 28.11.2016, 11:53 by M. Delnord, A. D. Hindori-Mohangoo, L. K. Smith, K. Szamotulska, J. L. Richards, P. Deb-Rinker, J. Rouleau, P. Velebil, I. Zile, L. Sakkeus, M. Gissler, N. Morisaki, S. M. Dolan, M. R. Kramer, M. S. Kramer, J. Zeitlin, Euro-Peristat Scientific Committee
OBJECTIVE: Concerns about differences in registration practices across countries have limited the use of routine data for international very preterm birth (VPT) rate comparisons. DESIGN: Population-based study. SETTING: Twenty-seven European countries, the United States, Canada and Japan in 2010. POPULATION: A total of 9 376 252 singleton births. METHOD: We requested aggregated gestational age data on live births, stillbirths and terminations of pregnancy (TOP) before 32 weeks of gestation, and information on registration practices for these births. We compared VPT rates and assessed the impact of births at 22-23 weeks of gestation, and different criteria for inclusion of stillbirths and TOP on country rates and rankings. MAIN OUTCOME MEASURES: Singleton very preterm birth rate, defined as singleton stillbirths and live births before 32 completed weeks of gestation per 1000 total births, excluding TOP if identifiable in the data source. RESULTS: Rates varied from 5.7 to 15.7 per 1000 total births and 4.0 to 11.9 per 1000 live births. Country registration practices were related to percentage of births at 22-23 weeks of gestation (between 1% and 23% of very preterm births) and stillbirths (between 6% and 40% of very preterm births). After excluding births at 22-23 weeks, rate variations remained high and with a few exceptions, country rankings were unchanged. CONCLUSIONS: International comparisons of very preterm birth rates using routine data should exclude births at 22-23 weeks of gestation and terminations of pregnancy. The persistent large rate variations after these exclusions warrant continued surveillance of VPT rates at 24 weeks and over in high-income countries.


This study was funded by grants from the European Commission for the Euro-Peristat project: 2010 13 01 and for the Bridge Health project: 664691. The funding agency was not involved in the study. MD received doctoral funding from Paris Descartes University, Paris, France. JLR received support from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) of the National Institutes of Health (NIH) T32 Predoctoral Training Program in Reproductive, Perinatal, and Pediatric Epidemiology under Award Number T32HD052460. NM was supported by the Japan Ministry of Health, Labor and Welfare (H28-ICT-001) and the Japan Agency for Medical Research and Development (AMED-6013). LKS is funded by a National Institute for Health Research Career Development Fellowship. This article presents independent research funded by the National Institute for Health Research (NIHR).



BJOG: An International Journal of Obstetrics and Gynaecology, 2016

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/Organisation/COLLEGE OF MEDICINE, BIOLOGICAL SCIENCES AND PSYCHOLOGY/School of Medicine/Department of Health Sciences


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BJOG: An International Journal of Obstetrics and Gynaecology


Wiley, Royal College of Ostetricians and Gynaecologist (RCOG)





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