By: 3 July 2012

Nearly 15 million babies were born prematurely in 2010 – more than one in ten of all births. Sixty percent of these premature babies were born in south Asia and sub-Saharan Africa, but this is not just a problem of the poorest nations: the USA (517,000 preterm births) and Brazil (279,300) ranked in the top ten countries with the highest number of premature births in 2010. Worse still, over the past 20 years preterm birth rates have decreased in just three countries, according to the first ever national level estimates and time series published in The Lancet.

“Our estimates highlight a fact that has received little attention. Most European countries have about half the preterm birth rate of the USA, but whilst the US rate has levelled off, European rates, even in Scandinavian countries, are increasing”, explains Joy Lawn from Save the Children in South Africa, who led the team producing the estimates for the World Health Organisation, published in the report Born Too Soon.

Preterm birth (before 37 weeks gestation) remains the single biggest cause of neonatal death worldwide and is now the second most common cause of death in children under five, responsible for 1.1 million deaths every year.

In this study, Lawn and colleagues used data from a number of sources including National Registries and Reproductive Health Surveys, and employed statistical modelling to assess data for 184 countries to estimate preterm birth rates for 2010 by country, region, and globally. They also calculated time trends since 1990 for 65 countries which had reliable data in developed regions, Latin America, and the Caribbean.

Numbers of premature births increased in most of the 65 countries. Only in Croatia, Ecuador, and Estonia did the preterm birth rate decrease between 1990 and 2010, whilst in 14 other countries the rate remained stable (less than 0.5% annual change).

The average rate in the 65 countries increased from 7.5% in 1990 (total preterm births two million) to 8.6% in 2010 (total preterm births 2.2 million).

The European countries with the greatest average increase in rates per year since 1990 were Cyprus (2.8%); Slovenia (2.6%); Belgium (2.5%); Austria (2.3%); Spain (2.2%); Ireland (2.1%); Portugal (1.9%); Greece (1.9%), France (1.6%), the UK (1.5%), and Bosnia (1.5%). By contrast, the USA had an average annual increase of just 0.7%.

The authors conclude: “The countries with the fastest increases include many European countries, and in many cases the reasons are not clear although the effects on families and the health system are very apparent. Urgent attention is needed to better understand and reduce these rates of preterm birth. At the same time we are very clear what can be done to save the lives of babies born preterm and urgent action to provide feasible, lifesaving care in African and South Asian countries would result in rapid decreases in deaths.”

In a linked comment, Nils-Halvdan Morken from University of Bergen and Haukeland University Hospital in Norway discusses the economic burden from preterm birth: “In the USA, the Institute of Medicine estimated that preterm birth costs the country at least US$26.2 billion a year or $51,600 per preterm infant. This group of infants accounts for 12% of US livebirths per year, but their care consumes close to 60% (or $6 billion) of total spending on initial neonatal care. The expenses are clearly related to gestational age; an infant born at 38 weeks incurs a tenth of the expense of one born at 35 weeks ($441 vs $4,733). Therefore, even a modest reduction in preterm birth would lead to substantially reduced costs.”

He also added: “Worldwide investment in maternal health and pregnancy will reduce suffering and probably save life years at a scale never before seen in the history of public health.”