International infant mortality rates: bias from reporting differences.

International infant mortality statistics have caused concern in the United States, since the US ranking relative to other developed countries has declined since World War II. This paper suggests that there may be international differences in reporting of very-low-birthweight infants and perinatal deaths and that such reporting differences bias comparisons of national perinatal and infant mortality rates. Efforts must be made to adopt standard conventions for the inclusion of small, early infants and fetal deaths in rate calculations.