More than 20 million babies were born with a low birth weight (less than 2500g; 5.5 pounds) in 2015—around one in seven of all births worldwide according to the first-ever estimates documenting this major health challenge.
These findings and more are documented in a new research paper developed by experts from the World Health Organisation (WHO), UNICEF and the London School of Hygiene & Tropical Medicine, published in The Lancet Global Health.
More than 80% of the world’s 2.5 million newborns who die every year are of low birth weight. Those low birth weight babies who survive have a greater risk of stunting, and developmental and physical ill health later in life, including diabetes and cardiovascular disease.
“Low birth weight is a complex clinical entity composed of intrauterine growth restriction and preterm birth,” says co-author Dr Mercedes de Onis from the Department of Nutrition at WHO.
“This is why reducing low birth weight requires an understanding of the underlying causes in a given country. For example, in Southern Asia a large proportion of low birth weight babies are born at term but with intrauterine growth restriction, which is associated with maternal under-nutrition, including maternal stunting.
“Conversely, preterm birth is the major contributor to low birth weight 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.”
Although close to three-quarters were born in Southern Asia and sub-Saharan Africa, the problem remains substantial in high-income countries in Europe, North America, Australia and New Zealand. High-income countries have seen virtually no progress.
What is being done to tackle this major public health problem
Reducing the incidence of low birth weight requires a comprehensive global strategy, which must include improving maternal nutritional status; treating pregnancy-associated conditions such as pre-eclampsia (hypertensive disease of pregnancy); and providing adequate maternal care, perinatal clinical services and social support.
Affordable, accessible and appropriate health-care is critical for preventing and treating low birth weight. Reductions in death, illness and disability in newborn babies will only be achieved if pregnancy care is fully integrated with appropriate care for low birth weight babies.
With continued momentum on child survival and health, including early childhood development, these new LBW estimates provide an opportunity to advance the agenda and call on all stakeholders to take concerted action in the effort to ensure that every newborn is weighed at birth, and that the information is collated and used for local action and accountability at the household, community, district, national, and global levels. At the same time, we must improve care for the 20.5 million LBW infants and their families each year.