The overall public health importance of LBW is determined not only by the risks for subsequent morbidity and mortality, but also by how frequently it occurs, i.e., its prevalence in a given population. The best available global estimates of mean birth weight and the prevalence of LBW were produced by WHO in 1979 (20) and updated to 1982 (21) (Table 1). Of
the 127 million infants born in the world in 1982, 20 million (16%) were estimated to weigh less than
2500 g, and over 90% of these infants were born in developing countries, a function not only of the
higher birth rate in these countries but also of their much higher prevalence of LBW.