Fetal electrocardiogram waveform analysis in labour

Abstract

Purpose of review: ST-waveform analysis of the fetal electrocardiogram (ECG) has emerged from experimental and observational studies to clinical use based on the outcome of two large randomized controlled trials and a European Union-supported project on the structured dissemination of knowledge and experience by establishing regional centres of excellence. The review focuses on the outcome from the host of studies and those recently published.

Recent findings: The database is dominated by a Swedish randomized controlled trial demonstrating not only improved outcome with regard to cord-artery metabolic acidosis and fewer operative interventions for non-reassuring fetal state but, most importantly, the marked and significant reduction in the risk of neonates showing signs of moderate or severe neonatal encephalopathy. The first report from the European Union project is presented, verifying the clinical relevance of the STAN methodology. The outcome of the large European Union project of 8000 deliveries confirms the observations of the randomized controlled trials. A study on the outcome shows improvements in accuracy and consistency among clinicians when automated ST analysis is added to the fetal heart rate trace.

Summary: After years of dedicated research, it appears as though ST analysis of the fetal ECG has become an additional source of information allowing detailed analysis of fetal responses and more accurate identification of a non-reassuring fetal status. The technology provides continuous information throughout labour. As with any new methodology, structured efforts on training and user feedback are required to fully implement the STAN methodology in clinical practice.