Which of the following factors stimulates a newborn's first breath?
A) Increasing concentration of carbon dioxide
B) Decreasing pH
C) Low oxygen concentration
D) All of the above

Question

Quizplus · Accepted Answer

All of the listed factors (increasing concentration of carbon dioxide, decreasing pH, and low oxygen concentration) can stimulate a newborn's first breath. As the infant is delivered and the umbilical cord is clamped, the source of oxygen and elimination of carbon dioxide is cut off, leading to a build-up of CO2 and a decrease in pH. Additionally, the low oxygen concentration in the outside environment further stimulates the baby to take its first breath.

Which of the Following Factors Stimulates a Newborn's First Breath