Born too soon: the global epidemiology of 15 million preterm births

Abstract

This second paper in the Born Too Soon supplement presents a review of the epidemiology of preterm birth, and its burden globally, including priorities for action to improve the data. Worldwide an estimated 11.1% of all livebirths in 2010 were born preterm (14.9 million babies born before 37 weeks of gestation), with preterm birth rates increasing in most countries with reliable trend data. Direct complications of preterm birth account for one million deaths each year, and preterm birth is a risk factor in over 50% of all neonatal deaths. In addition, preterm birth can result in a range of long-term complications in survivors, with the frequency and severity of adverse outcomes rising with decreasing gestational age and decreasing quality of care. The economic costs of preterm birth are large in terms of immediate neonatal intensive care, ongoing long-term complex health needs, as well as lost economic productivity. Preterm birth is a syndrome with a variety of causes and underlying factors usually divided into spontaneous and provider-initiated preterm births. Consistent recording of all pregnancy outcomes, including stillbirths, and standard application of preterm definitions is important in all settings to advance both the understanding and the monitoring of trends. Context specific innovative solutions to prevent preterm birth and hence reduce preterm birth rates all around the world are urgently needed. Strengthened data systems are required to adequately track trends in preterm birth rates and program effectiveness. These efforts must be coupled with action now to implement improved antenatal, obstetric and newborn care to increase survival and reduce disability amongst those born too soon.

Figure 1

Estimated distribution of causes of 3.1 million neonatal deaths in 193 countries in 2010. Source: Updated from Lawn et al., 2005, using data from 2010 published in Liu L, et al., 2012.

Figure 2

Overview of definitions for preterm birth and related pregnancy outcomes. Source: Reproduced with permission from Blencowe et al. (2012) National, regional and worldwide estimates of preterm birth rates in the year 2010 with time trends since 1990 for selected countries: a systematic analysis and implications. Lancet 379(9832): 2162-2172.

Figure 3

Preterm births by gestational age and region for the year 2010. Based on Millennium Development Goal regions. Source: Reproduced with permission from Blencowe et al. (2012) National, regional and worldwide estimates of preterm birth rates in the year 2010 with time trends since 1990 for selected countries: a systematic analysis and implications. Lancet 379(9832): 2162-2172.

Figure 4

Preterm births in 2010. Source: Blencowe, H., et al. (2012) Chapter 2: 15 million preterm births: Priorities for action based on national, regional and global estimates. In Born Too Soon: the Global Action Report on Preterm Birth. http://www.who.int/pmnch/media/news/2012/borntoosoon_chapter2.pdf 2012 [79]. Not applicable = non WHO Members State.