Diagnosis of foetal asphyxia in labour.

For many years intermittent recording of the foetal heart rate with a stethoscope and the detection of meconium in the liquor have been the only signs used for diagnosing intrapartum foetal asphyxia. Although the system has the virtue of simplicity, the unexpected disappearance of foetal heart sound when the foetal heart rate was being recorded as normal, or the frequent delivery of a vigorous baby when a firm diagnosis of foetal distress had been made, have served as constant reminders that more precise tools are needed. Recently, with the technical improvement in electronic recording, it has become possible to obtain a continuous record of the foetal cardiac activity. At the same time the assessment of the significance of abnormalities of the foetal heart rate has been improved by measuring the pH of foetal blood obtained by the technique of foetal blood sampling (Saling, 1962). In this paper the advantages and limitations of these two techniques for diagnosing foetal asphyxia will be decribed.