ST waveform of the fetal intrapartum electrocardiogram for the diagnosis and prevention of perinatal asphyxia

Intrapartum hypoxia is a recognized cause of fetal morbidity and mortality. However we recognize that the consequences of a severe lack of oxygen will vary from one fetus to another and the capacity of fetuses to handle hypoxia may differ greatly depending also on the situation prior to the actual hypoxic event. it is recognized that cardiolocography does not provide all the information we require to specifically interpret fetal reactions to labour stress. Fetal blood sampling can be used along with CTG monitoring to assess fetal acid-base status during labour and can reduce operative intervention but it requires additional expertise, is time consuming, gives only intermittent information and is therefore not widely used. Fetal pulse oximetry is focused on recording the actual level of fetal hypoxemia. However at present the ability of CTG plus pulse oximetry to provide diagnostic capacity on fetal metabolic acidosis have not yet been demonstrated. Extensive experimental work indicate that analysis of changes in ST waveform provide continuous information on metabolic events occurring within myocardial cells which allow cardiac function to be maintained during hypoxia. Clinical studies have shown that ST analysis of the fetal ECG provide usefııl information on fetal reaction to labour. Randomized controlled trials have provided conclusive evidence that ST waveform analysis can safely reduce the number of obstetric operative intervention with a parallel improvement in fetal outcome. in a European Commission supported project, involving ten European perinatal centres, the clinical, introduction of ST waveform analysis has been accompanied by a specifically developed model of teaching, training and staff accreditation. The results of the project show a significant improvement in fetal outcome with the combined use of CTG and ST waveform analysis. These results show that, through the appropriate use of proven technology and specific models of training and management, a safe reduction in the risk of babies being affected by oxygen deficiency during labour can be achieved with a significant reduction in the need for operative interventions.