More than a century ago, the leaders of public health identified the infant mortality rate as a key measure to assess and understand the health of society.1 Today, the infant mortality rate of a country or region remains an important marker of public health in many parts of the world for the reasons articulated 100 years ago. In countries with advanced health care systems, however, the infant mortality rate of groups of infants has assumed a new set of roles that can only be properly performed if we pay close attention to the manner in which newborns in these countries die.