NREMT Paramedic Practice

What circulatory pattern change occurs at birth?

1. Increased blood flow to the lungs

2. Decreased blood pressure

3. Increased heart rate

4. Decreased oxygen saturation

The correct answer is: Increased blood flow to the lungs

At birth, the circulatory system undergoes significant changes to adapt from fetal to neonatal life. The most notable change is the increase in blood flow to the lungs. Prior to birth, the fetus receives oxygenated blood from the placenta, and the lungs are filled with fluid, leading to low blood flow in that area. However, when the baby is born and takes its first breath, the lungs expand, and the resistance in the pulmonary circulation decreases dramatically. This causes blood to flow into the lungs, allowing for gas exchange and oxygenation, marking a critical shift necessary for survival outside the womb. The increase in blood flow to the lungs is essential for initiating respiratory function and ensuring the newborn receives adequate oxygen. This change also facilitates the closure of fetal structures such as the ductus arteriosus and foramen ovale, which are pivotal during fetal circulation but become unnecessary and are functionally closed after birth.