What is the primary fetal response to hypoxemia?

• A. Bradycardia
• B. Tachycardia
• C. Variable decelerations
• D. No change

Answer: (B)

When oxygen drops, the fetus first mounts a compensatory response by increasing heart rate. This tachycardia is the initial and primary reaction intended to boost cardiac output and help maintain blood flow to essential organs despite lower oxygen levels. If hypoxemia persists and worsens, the heart can begin to fail and bradycardia may develop, with patterns like late decelerations indicating advancing fetal compromise. Decelerations from cord compression (variable) reflect a different mechanism, not the general hypoxemic response. No change would not describe the early, automatic adjustment the fetus makes to conserve oxygen.