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

How does the fetal heart rate (FHR) baseline change over the course of pregnancy?

1. Increases

2. Decreases

3. Remains constant

4. Fluctuates regularly

The correct answer is: Decreases

The baseline fetal heart rate (FHR) typically decreases during the course of pregnancy. Initially, the FHR is generally higher in early pregnancy and can range from about 160 to 180 beats per minute. As the pregnancy progresses, the baseline heart rate tends to decrease to a more stable range of approximately 120 to 160 beats per minute, aligning more closely with the heart rates seen in neonates. This decrease in FHR is influenced by several physiological changes. As the fetus grows, the autonomic nervous system matures, which helps in regulating heart rate more effectively. Additionally, increased oxygenation and development of a more robust cardiovascular system contribute to this normalization of heart rate patterns. Understanding this trend is crucial for monitoring fetal well-being during prenatal care, as deviations from the expected baseline may signal potential issues that require further evaluation and intervention.