More than 20 million infants are born each year weighing less than 2,500 grams (5.5 pounds), accounting for 17 per cent of all births in the developing world – a rate more than double the level in industrialized countries (7 per cent).9 Infants with low birthweight are at higher risk of dying during their early months and years. Those who survive are liable to have an impaired immune system and may suffer a higher incidence of such chronic illnesses as diabetes and heart disease in later life.
More than 96 per cent of low birthweight occurs in the developing world, reflecting the higher likelihood of these babies being born in poor socio-economic conditions, where women are more susceptible to poor diet and infection and more likely to undertake physically demanding work during pregnancy.10 It reflects, further, a generational cycle of undernutrition, the consequences of which are passed along to children by mothers who are themselves in poor health or undernourished.
There is significant variation in the incidence of low birthweight across regions. South Asia has the highest incidence, with 31 per cent of all infants with low birthweight, while East Asia/Pacific has the lowest, at 7 per cent. India is home to nearly 40 per cent of all low-birthweight babies in the developing world. In sub-Saharan Africa 14 per cent and in the Middle East/North Africa 15 per cent of infants are born with low weight.
Reliable monitoring of this vital indicator is difficult, however, given that 58 per cent of all infants in the developing world are not weighed at birth. This proportion is highest in South Asia (74 per cent) and sub-Saharan Africa (65 per cent).11
Trend analysis is also difficult due to the lack of comparable estimates over time, both within and between countries. However, an analysis of limited trend data indicates that the incidence of low birthweight remained roughly constant between 1990 and 2000 in both sub-Saharan Africa and Asia.12
9 Incidence of low birthweight is based on latest available estimates during 1998–2004.
10 United Nations Children’s Fund and the World Health Organization, Low Birthweight: Country, regional and global estimates, UNICEF and WHO, New York and Geneva, 2004, pp. 2–3.
11 United Nations Children’s Fund and the World Health Organization, Low Birthweight: Country, regional and global estimates, UNICEF and WHO, New York and Geneva, 2004, p. 9.
12 Trend estimates of low birthweight are based on surveys in 20 developing countries, covering about half of the developing world’s population (excluding China). See also Low Birthweight: Country, regional and global estimates, UNICEF and WHO, New York and Geneva, 2004.