FHR Variability Categories


(Depending on size)

  • Fetal heart rate is constantly varying from the baseline; this variability reflects a healthy fetal nervous system and cardiac responsiveness.
  • These fluctuations are characterized as absent if there is no variation in the amplitude range, minimal if fluctuation is less than 5 bpm, moderate if fluctuation is 6 to 25 bpm, and marked if fluctuation is greater than 25 bpm.
  • Absent variability indicates fetal academia but marked, moderate, and even minimal variation rules it out.
  • Conditions like fetal hypoxia, congenital heart anomalies, and fetal tachycardia can cause a decrease in variability.