NCC Certified Electronic Fetal Monitoring (C-EFM) Practice Exam

Which FHR pattern is likely to develop with severe fetal anemia?

1. Accelerated

2. Regular

3. Sinusoidal

4. Bradycardic

The correct answer is: Sinusoidal

The correct answer is sinusoidal. Sinusoidal fetal heart rate (FHR) patterns are characterized by a smooth, wave-like appearance and are often associated with severe fetal anemia, particularly due to conditions such as Rh incompatibility or fetomaternal hemorrhage. This particular pattern indicates a serious and immediate concern for the fetus, often reflecting a compromised state. In the context of severe fetal anemia, the sinusoidal pattern can emerge because it represents the body's response to inadequate oxygenation. The regular oscillations of the heart rate are thought to be a response to fetal blood volume status and are indicative of possible underlying distress and hypoxia. Thus, the appearance of this pattern requires immediate medical evaluation and intervention. Other FHR patterns such as accelerated or regular would not typically indicate severe fetal anemia and could suggest more stable conditions. A bradycardic pattern, on the other hand, while concerning, does not represent the specific oscillatory nature of sinusoidal tracings. Instead, it suggests a slower than normal heart rate and can point towards other issues, but is not characteristically linked to the same immediate physiological conditions associated with severe fetal anemia.