[Continuous fetal biochemical monitoring and cardiotocography].
Changes in fetal scalp transcutaneous PO2 (tcPO2) were compared with those of the fetal heart rate (FHR) in 31 high-risk pregnancies. Fetal tcPO2 at 10 minutes prior to the delivery was quite similar to umbilical arterial PO2. The abnormal FHR pattern evaluated by the FHR score was well correlated with the fetal tcPO2, umbilical arterial PO2, umbilical arterial pH and Apgar score. When there were signs of fetal distress in the FHR pattern, such as late deceleration, severe variable deceleration, or prolonged fetal bradycardia, the tcPO2 was lower than 15mmHg, and there occurred a temporary fall in tcPO2 of more than 5mmHg. It was concluded that proficiency in evaluating FHR tracings might eliminate the necessity of fetal biochemical monitoring, including fetal blood sampling, and also decrease the frequency of cesarean sections for fetal distress.