Final answer:
The elevated hematocrit level in a postterm infant is most likely the result of hypoxia in utero. During pregnancy, if the infant experiences inadequate oxygen supply, their body compensates by producing more red blood cells, leading to a higher hematocrit level.
Step-by-step explanation:
The elevated hematocrit level in a postterm infant is most likely the result of hypoxia in utero. During pregnancy, if the infant experiences inadequate oxygen supply, their body compensates by producing more red blood cells, leading to a higher hematocrit level. This is a physiological response to low oxygen levels and is commonly seen in postterm infants.