Continuous tissue pH monitoring in the term fetus

Since Saling's work in 1961, many investigators have attempted to perfect methods to detect fetal acidosis during labor. A system for continuous tissue pH monitoring of the fetus is evaluated in this study of 59 patients. There was poor correlation of tissue pH values and capillary scalp pH values in 19 cases (r = 0.487), and no significant correlation of tissue pH values to the outcome measurements of Apgar scores and cord gas levels. The benefits realized were those of monitoring the trend of tissue pH over time. We believe that a continuous pH monitoring system offers several advantages over intermittent fetal scalp sampling. Further refinement of the technology employed may offer such a system in the future.