Practical experience in the usage of a pH electrode.

A total of 57 continuous pH measurements have been carried out at the University Clinic of Gynecology in Graz since September 1976. In 41 cases diagrams were suitable for evaluation. In fetal distress the pH curves showed increasing waves synchronous with labor activity. A linear pH curve seems to preclude imminent danger to the fetus. A decline in the pH curve prior to delivery may be caused either mechanically or by fetal distress.