The infant mortality rate of a society is a recognized indicator of its overall health
Most premature and low birth weight babies need to stay in the hospital for a long time, and the United States has developed and has very skilled skills in this area
 Although infant mortality rates are higher in some parts of the United States than in many developing countries, the overall rate in the United States has been declining, but this decline does not necessarily mean that, on average, babies in the United States are born healthier than before