Bulletin of the World Health Organization

The worldwide incidence of preterm birth: a systematic review of maternal mortality and morbidity

Stacy Beck, Daniel Wojdyla, Lale Say, Ana Pilar Betran, Mario Merialdi, Jennifer Harris Requejo, Craig Rubens, Ramkumar Menon & Paul FA Van Look

Volume 88, Number 1, January 2010, 31-38

Table 1. Variables included in the regression model, number of countries modelled, and predictive power of the model, by region, in a systematic review of the worldwide incidence of preterm birth

Region/groupinga Predictor variableb No. of countries modelled/total Adjusted R²
Africa Proportion of urban population 30/52 0.644
Total expenditure on health
Life expectancy at birth (male)
Under-five mortality
Asia Government expenditure on health 25/47 0.424
Low birth weight
Under-five mortality
Human development index
Europe, North Americac and Australia and New Zealand Immunization coverage for DPT3 9/43 0.421
Total expenditure on health
Government expenditure on health
Healthy life expectancy at birth (adult, female)
Latin America and the Caribbean and Oceania (excluding Australia and New Zealand) Immunization coverage for measles 23/37 0.603
Per capita total expenditure on health
Mortality rate (females)
Low birth weight

DPT3, diphtheria, pertussis and tetanus, third and final dose.
a For application of models, country groupings were defined based on sociodemographic similarities.
b See Appendix A (http://www.who.int/reproductivehealth/publications/monitoring/en/index.html) for definitions and sources of variables.
c In this analysis, Mexico was included in Latin America rather than North America.

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