Fetal brain damage develops after the loss of FHR variability followed by infantile cerebral palsy due to severe hypoxia
in frequently repeated fetal heart rate (FHR) decelerations (transient bradycardia) or prolonged fetal bradycardia, where
novel hypxia index is 25 or more, and it is prevented if the hpoxia index is 24 or less. The hypoxia index (HI) is the sum of
FHR deceleration durations (min) divided by the lowest FHR (bpm), and multiplied by 100 (Figure 1). The HI is calculated
by visual measurement, while it is also suitably calculated by computerized FHR monitoring. Cerebral palsy is prevented
when HI is 24 or less with almost zero error probability in the delivery. The cases whose HI was 25 or more will develop
cerebral palsy, thus, it can receive early cerebral palsy trearments in neonatal stage. As late deceleration disappeared
when the parturient woman changed her posture to lateral one from supine, a parturient woman is recommended to have
lateral posture, when they notice the appearance of FHR deceleration during the delivery to disappear deceleration to
prevent the increase of HI value. As the HI is adopted not only late deceleration, but also all decelerations and continuous
bradycardia, fetal diagnosis will change to objective numeric FHR analysis from the monitoring with vague subjective FHR
pattern classification.
Rise & Fall of Fetal Heart Rate, the Principle of Fetal Monitoring: Hypoxia Index prevents Cerebral Palsy
