Birth weight

Birth weight is the body weight of a baby at their birth.^[1] The average birth weight in babies of European and African descent is 3.5 kilograms (7.7 lb), with the normative range between 2.5 and 4.0 kilograms (5.5 and 8.8 lb).^[2] On average, babies of Asian descent weigh about 3.25 kilograms (7.2 lb).^[3][4] The prevalence of low birth weight has changed over time. Trends show a slight decrease from 7.9% (1970) to 6.8% (1980), then a slight increase to 8.3% (2006), to the current levels of 8.2% (2016).^[5][6] The prevalence of low birth weights has trended slightly upward from 2012 to the present.^[7]

Low birth weight is associated with neonatal infection, infant mortality, as well as illness into adulthood.^[8] Numerous studies that have attempted, with varying degrees of success, to show links between birth weight and later-life conditions, including diabetes, obesity, tobacco smoking, and intelligence.^[9]