First experience with continuous pH measurements on fetus during delivery.

First experience with continuous pH measurement is reported. It was possible to apply well calibrated electrodes to the fetal scalp in 22 cases. Of these 22 cases eight must be regarded as failures because of unstable values. Of the remaining 14 measurements, seven were of good (or acceptable) quality and seven of poor quality. The size of the electrodes and the excessive depth of penetration are probable reasons for these failures. An important condition for obtaining reliable pH values is a perpendicular position of the electrode in the fetal scalp. An indicator for correct position of the electrode appears to be the irregularity in the recording of the pH curve. Experience so far indicates that the pH electrode in its present form is not suitable for routine use.