Preventing preterm births: analysis of trends and potential reductions with interventions in 39 countries with very high human development index

Abstract

Background: Every year, 1·1 million babies die from prematurity, and many survivors are disabled. Worldwide, 15 million babies are born preterm (<37 weeks' gestation), with two decades of increasing rates in almost all countries with reliable data. The understanding of drivers and potential benefit of preventive interventions for preterm births is poor. We examined trends and estimate the potential reduction in preterm births for countries with very high human development index (VHHDI) if present evidence-based interventions were widely implemented. This analysis is to inform a rate reduction target for Born Too Soon.

Methods: Countries were assessed for inclusion based on availability and quality of preterm prevalence data (2000-10), and trend analyses with projections undertaken. We analysed drivers of rate increases in the USA, 1989-2004. For 39 countries with VHHDI with more than 10,000 births, we did country-by-country analyses based on target population, incremental coverage increase, and intervention efficacy. We estimated cost savings on the basis of reported costs for preterm care in the USA adjusted using World Bank purchasing power parity.

Findings: From 2010, even if all countries with VHHDI achieved annual preterm birth rate reductions of the best performers for 1990-2010 (Estonia and Croatia), 2000-10 (Sweden and Netherlands), or 2005-10 (Lithuania, Estonia), rates would experience a relative reduction of less than 5% by 2015 on average across the 39 countries. Our analysis of preterm birth rise 1989-2004 in USA suggests half the change is unexplained, but important drivers include non-medically indicated labour induction and caesarean delivery and assisted reproductive technologies. For all 39 countries with VHHDI, five interventions modelling at high coverage predicted a 5% relative reduction of preterm birth rate from 9·59% to 9·07% of livebirths: smoking cessation (0·01 rate reduction), decreasing multiple embryo transfers during assisted reproductive technologies (0·06), cervical cerclage (0·15), progesterone supplementation (0·01), and reduction of non-medically indicated labour induction or caesarean delivery (0·29). These findings translate to roughly 58,000 preterm births averted and total annual economic cost savings of about US$3 billion.

Interpretation: We recommend a conservative target of a relative reduction in preterm birth rates of 5% by 2015. Our findings highlight the urgent need for research into underlying mechanisms of preterm births, and development of innovative interventions. Furthermore, the highest preterm birth rates occur in low-income settings where the causes of prematurity might differ and have simpler solutions such as birth spacing and treatment of infections in pregnancy than in high-income countries. Urgent focus on these settings is also crucial to reduce preterm births worldwide.

Funding: March of Dimes, USA, Eunice Kennedy Shriver National Institute of Child Health and Human Development, and National Institutes of Health, USA.

Figure 1. Country selection process for preterm birth rate trends analyses

a. Inclusion criteria for countries with reliable preterm birth trend data b. Examination of “high-income” country groupings with best fit for countries with high-quality preterm birth data Notes: Data on preterm prevalence from Blencowe H et al Lancet 2012.For country groupings see webappendix webtable 1, p. 1-2

Figure 1. Country selection process for preterm birth rate trends analyses

a. Inclusion criteria for countries with reliable preterm birth trend data b. Examination of “high-income” country groupings with best fit for countries with high-quality preterm birth data Notes: Data on preterm prevalence from Blencowe H et al Lancet 2012.For country groupings see webappendix webtable 1, p. 1-2

Figure 2. Preterm birth trend data availability by country, 1990-2010

Notes: Data on preterm prevalence data availability from Blencowe H et al Lancet 2012 Some countries with high quality data only had data for subnational populations eg UK, Belgium

Figure 3. Preterm birth rates and time trends for Very High Human Development Index countries

a: Preterm birth rates per 100 live births in 2010 (baseline) for 39 Very High Human Development Index countries b. Average Annual Rate of Change (AARC) in preterm rates 2000-2010 for 26 Very High Human Development Index countries with high-quality data and >10,000 births c.Average Annual Rate of Change (AARC) groupings 2000-2005, 2010 for 23 Very High Human Development Index countries with preterm birth data spanning at least 5 years within each 6 year period

Figure 3. Preterm birth rates and time trends for Very High Human Development Index countries

a: Preterm birth rates per 100 live births in 2010 (baseline) for 39 Very High Human Development Index countries b. Average Annual Rate of Change (AARC) in preterm rates 2000-2010 for 26 Very High Human Development Index countries with high-quality data and >10,000 births c.Average Annual Rate of Change (AARC) groupings 2000-2005, 2010 for 23 Very High Human Development Index countries with preterm birth data spanning at least 5 years within each 6 year period

Figure 3. Preterm birth rates and time trends for Very High Human Development Index countries

a: Preterm birth rates per 100 live births in 2010 (baseline) for 39 Very High Human Development Index countries b. Average Annual Rate of Change (AARC) in preterm rates 2000-2010 for 26 Very High Human Development Index countries with high-quality data and >10,000 births c.Average Annual Rate of Change (AARC) groupings 2000-2005, 2010 for 23 Very High Human Development Index countries with preterm birth data spanning at least 5 years within each 6 year period

Figure 4. Preterm birth rates for 2010 among Very High Human Development Index countries projected to 2015 considering various scenarios including averaged annual rate change (AARC) for top performing countries in different time periods, or high coverage of the five preventive interventions

Notes: See webappendix p.16-41 for details

Figure 5. Analysis of factors contributing to the increasing preterm birth rate in the United States (1989 to 2004)

Notes: See webappendix p.7-14 for details of analyses. Calculation of PAR aimed to take into account the existence of multiple risk factors in one woman, eg increased maternal age and ART use

Figure 6. Projected change from 2010 baseline preterm birth rate showing modelled contribution of the five selected interventions

a. For all 39 Very High Human Development Index countries b. For United States andSweden Notes: See webappendix p.16-41 for details of analyses, including input data and methods.

Figure 6. Projected change from 2010 baseline preterm birth rate showing modelled contribution of the five selected interventions

a. For all 39 Very High Human Development Index countries b. For United States andSweden Notes: See webappendix p.16-41 for details of analyses, including input data and methods.

Figure 7. Estimation of total preterm births averted by 2015 in 39 Very High Human Development Index countries, and cost savings incurred

Notes: Total economic cost associated with one preterm baby in the United States from The National Academy Press, Preterm Birth: Causes, Consequences, and Prevention report 2007. Purchasing power parity conversion factor and official exchange rates for each country in 2005 obtained from World Development Indicators, The World Bank and OECD Library. Total economic cost includes costs of medical care services, early intervention services, special education services, and lost household and labor market productivity. See webappendix p.32 - 33 for country-by-country estimates of preterm birth averted and cost savings.