Study in The Lancet Global Health highlights how little has been achieved on the global targets to reduce low birth weight babies
More than 20 million babies were born with a low birthweight (less than 2500g; 5.5 pounds) in 2015—around one in seven of all births worldwide. Almost three-quarters of these babies were born in Southern Asia and sub-Saharan Africa, where data are most limited.
However, the problem also remains substantial in high-income countries in Europe, North America, and Australia and New Zealand, where there has been virtually no progress in reducing low birthweight rates since 2000, according to a new analysis undertaken by researchers from the London School of Hygiene & Tropical Medicine, UNICEF, and the World Health Organization (WHO), involving 148 countries and 281 million births, published in The Lancet Global Health journal.
In 2012, all 195 member states of the WHO committed to a 30% reduction in low birthweight prevalence by 2025, compared with 2012 rates. 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).
“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, caesarean sections not medically indicated and fertility treatments that increase the risk of multiple births”
However, the study indicates 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 target of a 30% reduction in prevalence between 2012 and 2025.
These findings highlight the urgent need for more investment and action to accelerate progress, through understanding and tackling key drivers of low birthweight throughout life—including extremes of maternal age, multiple pregnancy, obstetric complications, chronic maternal conditions (eg, hypertensive disorders of pregnancy), infections (eg, malaria), and nutritional status, as well as exposure to environmental factors such as indoor air pollution, and 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, caesarean sections not medically indicated and fertility treatments that increase the risk of multiple births. These are the underlying issues that governments in high-income countries should be tackling,” 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.”
The study authors call for international action to ensure that all babies are weighed at birth, to improve clinical care, and to promote public health action on the causes of low birthweight to reduce death and disability.
“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 of care to these newborns and their mothers.”
More than 80% of the world’s 2.5 million newborns who die every year are low birthweight because they are either born preterm and/or small for gestational age. Low birthweight babies who survive have a greater risk of stunting, and developmental and physical ill health later in life, including chronic conditions such as diabetes and cardiovascular disease.
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.
Nevertheless, the overall number of low birthweight livebirths has actually increased in sub-Saharan Africa from 4.4 million to 5 million babies, largely due to demographic trends (such as fertility and migration). Similarly, Southern Asia still has almost half of the world’s low birthweight livebirths, with an estimated 9.8 million in 2015.
