FHR  Abnormal sign Evaluation score
FHR baseline 110-130 or 160-180 bpm 1
  <110 or >180 bpm 3
Deceleration    
Duration >60 sec 3
Amlitude >50 bpm 2
Nadir heart rate <100 bpm 2
Recovery time >40 sec 3
Lag time >40 sec 3
No associated acceleration   2
Loss of variability, W-shaped dip 4
Table 1: Calculation of the FHR score.