1 in 7 babies worldwide born with a low birthweight but the number of low birthweight babies stayed almost constant in Viet Nam over 15 years. – The Lancet Global Health, UNICEF, WHO

“This figure is most encouraging," said Rana Flowers, UNICEF Representative in Viet Nam, “however as a national average, it does not give us the complete picture and is likely to hide important disparities, for example among the poorest mothers, 28 per cent of whom do not have institutional deliveries, and their newborn’s weight is not usually recorded”, she added.

Assessing birthweight in 148 countries, reviewing 281 million births, the estimates, which are the first of their kind, found that worldwide low birthweight prevalence fell slightly from 17.5% in 2000 (22.9 million low birthweight livebirths) to 14.6% in 2015 (20.5 million). A similar pattern can be seen in Viet Nam, as the rate of low birthweight was reduced by only 1 per cent from 9.2 per cent in 2000 to 8.2 per cent in 2015, and the number of babies with low birthweight stayed almost constant at 130,000 per year over this period

Low birthweight is a significant contributor in more than 80% of cases of newborn death. For those babies that survive - they are at a greater risk of stunting, developmental and physical ill health later in life. Calling for urgent attention to reduce the number of babies born with low birthweight, the research challenges Governments in rich as well as poor countries to refocus and to do more.

“Improved levels can be achieved, with a stronger focus on maternal nutrition delivered in quality ante-natal care, and institutional delivery services for all mothers, especially the poorest and those in remote and mountainous areas. Likewise, a scaling up of nationwide interventions for premature and low birthweight babies, such as Early Essential Newborn Care and Kangaroo Mother Care – would also secure stronger results”, said Rana Flowers, UNICEF Representative in Viet Nam.

Furthermore, the study concludes that at the current rate of progress—with a 1.2% yearly decline in low birthweight rates between 2000 and 2015—the world will fall well short of the annual reduction rate of 2.7% required to meet the WHO agreed target of a 30% reduction in prevalence between 2012 and 2025.

The study authors call for international action to ensure that all babies are weighed at birth, improved clinical care, and promotion of public health action on the causes of low birthweight. They point to an urgent need for more investment and action to tackle the key drivers of low birthweight throughout life. Such drivers include extremes of maternal age, multiple pregnancies, obstetric complications, chronic conditions (eg, hypertension), infections (eg, malaria), and maternal nutritional status, as well as exposure to environmental factors such as indoor air pollution, tobacco and drug use. In low-income countries, poor growth in the womb is a major cause of low birthweight. In more developed regions, low birthweight is often associated with prematurity (a baby born earlier than 37 weeks gestation).

“Despite clear commitments, our estimates indicate that national governments are doing too little to reduce low birthweight. We have seen very little change over 15 years, even in high-income settings where low birthweight is often due to prematurity as a result of high maternal age, smoking, medically unnecessary caesarean sections and fertility treatments that increase the risk of multiple births…” says lead author Dr Hannah Blencowe from the London School of Hygiene & Tropical Medicine, UK. “To meet the global nutrition target of a 30% reduction in low birthweight by 2025 will require more than doubling the pace of progress.” [1]

In signalling concerns regarding lack of data in low and middle income countries, the report sounds a clear call to action to weigh every baby at birth. “Every newborn must be weighed, yet worldwide, we don’t have a record for the birthweight of nearly one third of all newborns,” says co-author Julia Krasevec, Statistics & Monitoring Specialist from UNICEF. “We cannot help babies born with low birthweight without improving the coverage and accuracy of the data we collect. With better weighing devices and stronger data systems, we can capture the true birthweight of every baby, including those born at home, and provide better quality care to these newborns and their mothers.” [1]

Almost three-quarters of low-birthweight babies were born in Southern Asia and sub-Saharan Africa, where data is more limited. However, researchers also noted a virtual lack of progress since 2000 in high-income countries in Europe, North America, Australia and New Zealand.

One of the lowest rates of low birthweight in 2015 was estimated in Sweden (2.4%). This compares to around 7% in some high-income countries including the USA (8%), the UK (7%), Australia (6.5%), and New Zealand (5.7%). The regions making the fastest progress are those with the highest numbers of low birthweight babies, Southern Asia and Sub-Saharan Africa, with a yearly decline in low birthweight prevalence of 1.4% and 1.1%, respectively, between 2000 and 2015. Southern Asia still has almost half of the world’s low birthweight livebirths, with an estimated 9.8 million in 2015 (table 4; figure 3).

“Low birthweight is a complex clinical entity composed of intrauterine growth restriction and preterm birth,” says co-author Dr Mercedes de Onis from WHO, Switzerland. “This is why reducing low birthweight requires understanding of the underlying causes in a given country. For example, in Southern Asia a large proportion of low birthweight babies are born at term but with intrauterine growth restriction, which is associated with maternal undernutrition including maternal stunting. Conversely, preterm birth is the major contributor to low birthweight in settings with many adolescent pregnancies, high prevalence of infection, or where pregnancy is associated with high levels of fertility treatment and caesarean sections (like in USA and Brazil). Understanding and tackling these underlying causes in high-burden countries should be a priority.” [1]

Notes to Editors

Download photos and broll here. To go through the Lancet paper, click here.

To review estimates and recommendations on tackling low birthweight by UNICEF and WHO, click here.

This study was funded by the Bill & Melinda Gates Foundation, The Children’s Investment Fund Foundation, United Nations Children’s Fund (UNICEF), and WHO. It was conducted by researchers from the London School of Hygiene & Tropical Medicine, London, UK; IRCCS Burlo Garofolo, Scientific Directorate, Trieste, Italy; World Health Organization, Geneva, Switzerland; UNICEF, NY, USA; Johns Hopkins University, Baltimore, MD, USA.

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[1] Quotes direct from authors and cannot be found in text of Article.