In Reply In the years since Dr Apgar’s score was published,1 our understanding of the sequence of physiological events occurring during the transition from intrauterine to extrauterine life has progressed. This knowledge helps inform the assessments and procedures that constitute the Neonatal Resuscitation Program.2 Oxygenation and changes in circulation culminate in tissue oxygen delivery. A score should reflect those steps. We assume that Apgar chose reflex irritability, which was a sneeze, grimace, or other response to having something stuck up the infant’s nose, as an indication that the brain was receiving sufficient oxygen and perfusion to do its functions. After routine suctioning was dropped as a standard maneuver during resuscitation, a variety of other stimuli, equally irritating, have been substituted.