Kazuo Maeda1* and Masaji Utsu2
1Department of Obstetrics and Gynecology, Tottori University Medical School, Japan
2Department of Obstetrics and Gynecology, Seirei Mikatahara Hospital, Japan
Fetal bradycardia is very important in fetal monitoring, as hypoxia stimulates vagus nerve center to develop fetal bradycardia, thus, a deceleration (transient fetal bradycardia) develops if fetal PaO2 is less than 50 mmHg. The hypoxia damages fetal central nervous system, if the hypoxic deceleration frequently repeated, and fetal brain lost the reaction to fetal movement and the baseline variability is lost in frequently repeated hypoxia, which is similar to anencephalic FHR, followed by infantile cerebral palsy. Thus, hypoxic fetus should be cured by early delivery before the loss of variability, where the threshold is shown by novel Hypoxia Index (HI), which is the sum of deceleration duration (min), divided by the lowest FHR (bpm), and multiplied by 100. The numeric threshold of no cerebral palsy is 24, namely, cerebral palsy is prevented if the HI is 24 or less in the labor. Neonate whose HI is 25 or more can be treated by early cerebral palsy therapy. Traditional FHR pattern classification is exchanged by such numeric methods as hypoxia index & deceleration area. A FHR deceleration should be rejected by maternal lateral posture to prevent large hazardous indices.
Fetal monitoring; Hypoxia index; Cerebral palsy; Late deceleration; Lateral posture
Maeda K, Utsu M. The Importance of Fetal Bradycardia in Fetal Heart Rate Monitoring. J Clin Obstet Gynecol Infertil. 2019; 3(1): 1037.