It is estimated that 15% to 20% of all babies born worldwide are low birth weight, representing more than 20 million births a year.
Defined by the World Health Organization (WHO) as weight at birth less than 2500 grams or 5.5 lbs, low birth weight is a major predictor of infant death and disease. Every year, 1.1 million babies die from complications of pre-term birth, including low birth weight. Low birth weight also increases the risk for non-communicable diseases later in life, such as diabetes and cardiovascular disease. The majority of low-birth-weight births occur in low- and middle-income countries, especially among the most vulnerable populations. Nevertheless, low birth weight is a global concern, as countries such as Spain, the United Kingdom and the United States face high rates of low birth weight.
In 2012, the World Health Assembly endorsed a global low birth weight target to reduce the number of infants born low birth weight by 30% by 2025.