Cardiotocography supplemented with continuous fetal pH monitoring during labor. Effect on rate of obstetrical interventions and neonatal condition.

Continuous monitoring of the fetal scalp tissue pH (tpH) was performed in 96 consecutive cases. Of these 96, 72 (75%) had acceptable pH tracings which were used for the management of labor (series II). These 72 patients were compared with 72 patients from an earlier series (series I) of tpH monitoring in which pH was not used in the management of labor (matched according to age and parity). A significant decrease in the number of forceps and vacuum extractions (from 25.8 to 8.6%) and in the total number of interventions (from 36.1 to 15.3%) because of suspected fetal distress was observed when tpH was used in the management of labor. The state of the newborns (Apgar score 1 and 5 min after delivery; umbilical artery and vein pH, pCO2, base excess, standard bicarbonate, pO2, oxygen saturation, and hemoglobin) was equal in the two series, except for a slightly greater oxygen saturation of the umbilical artery and a slightly lower umbilical vein pH in series II. It is concluded that tpH monitoring of the fetus during labor can reduce the number of interventions, but the method still needs further development and clinical evaluation.