The management of fetal distress with the use of fetal blood pH: A clinical review

Abstract

Fetal assessment and subsequent management of 137 patients with meconium or fetal heart rate abnormalities in the first stage of labor was determined by the fetal blood pH. In the majority of patients the fetal blood pH was 7.25 or more, and the fetus was considered to be adequately oxygenated. Twenty-three per cent of the fetuses were initially observed to have a pH of less than 7.25. Repeat pH estimations, both when the pH was between 7.15 and 7.25 and toward the end of labor, improved the diagnosis of intrauterine asphyxia. Fetal heart rate abnormalities as detected by auscultation were not commonly present in those patients with meconium in whom the fetal pH was less than 7.15. Seven cesarean sections were performed for fetal acidosis. There were 4 perinatal deaths, one of which was due to intrapartum anoxia. A significantly increased incidence of infants with low Apgar scores occurred among patients with a predelivery fetal blood pH of less than 7.25. The results suggest that a progressive deterioration of pH below 7.25 is an indication for intervention in labor and delivery of the fetus.