If a problem begins in utero, which is more likely to be compromised in the fetus?

• A. Blood flow
• B. Airway
• C. Lungs
• D. Heart rate

Answer: (A)

In the fetus, gas exchange and nutrient delivery depend entirely on placental blood flow. The lungs aren’t used for breathing yet—they’re fluid-filled and not responsible for oxygenating blood until after birth. So when a problem starts in utero, the first system that's likely compromised is the fetal blood flow, particularly placental perfusion and umbilical circulation, leading to reduced oxygen delivery. The airway and lungs aren’t the primary sites of compromise before birth, and while heart rate can be affected secondarily, the central issue is the circulation sustaining the fetus.