The continuous measurement of tissue pH in the human fetus during labour using a new application technique.

The subcutaneous tissue pH (tpH) of 61 fetuses has been measured continuously during labour using the tissue pH electrode designed by Stamm (Stamm et al, 1976) and adapted for use by Roche Medical and Laboratory Systems. These 61 fetuses fell chronologically into two groups: Group 1 comprised 31 fetuses in whom the original method of fixation to the fetal scalp was used, and Group 2 comprised 30 fetuses in whom the fixation apparatus incorporated the latest technical developments of the double spiral electrocardiograph (ECG) electrode and the fetal tpH Applicator Tool Set Model 678449. Better results were obtained with Model 678449.