North American Registry of Midwives (NARM) Practice Exam

How much pressure is needed for the first newborn breath?

1. 20 to 30 cm H2O

2. 30 to 40 cm H2O

3. 40 to 50 cm H2O

4. 50 to 60 cm H2O

The correct answer is: 40 to 50 cm H2O

The first breath of a newborn involves significant physiological changes as the baby transitions from a fluid-filled intrauterine environment to breathing air. The correct answer indicates that a pressure range of 40 to 50 cm H2O is typically required for the newborn to initiate effective breathing. This level of pressure reflects the need for the baby to overcome the surface tension in the alveoli, which are the tiny air sacs in the lungs, and to inflate them properly. During the first breath, the baby must generate enough negative pressure to draw air into the lungs, and achieving this pressure range is essential for establishing functional residual capacity in the lungs. The correct pressure helps to ensure that the alveoli remain open and facilitates adequate gas exchange, which is crucial for the newborn’s survival immediately after birth. Understanding this pressure requirement highlights the importance of respiratory mechanics in the early neonatal period and the physiological readiness of the newborn to transition to independent breathing.