Erroneous Recording of Maternal Heart Rate as Fetal Heart Rate During Second Stage of Labour: Isn’t it Time to Stop this?

Abstract

Electronic Fetal Heart Rate (FHR) monitoring is recommended to assess fetal well-being during labour in high risk pregnancies. This Cardiotocograph (CTG) monitoring relies on the ultrasound technology with the limitation of signal loss in 15% to 40% of the cases [1]. In the earlier versions of these CTG monitors, fetal heart tracings were generally of reasonable quality with many artefacts and some degree of occasional large signal noise. Subsequent models were improved by signal modulation and autocorrelation. Although, these new methodologies of signal processing have reduced the signal loss, the issues of inadvertent monitoring of the maternal heart rate as fetal heart rate and inaccurate evaluations of baseline fetal heart rate (i.e. doubling or halving) continue to pose difficulties during intrapartum fetal heart rate monitoring.