Signal Ambiguity and Misinterpretation of Fetal Heart Rate: A Report of Two Cases and an Overview of Suspicious Patterns

Abstract

Electronic Fetal Heartrate Monitoring (EFHM) is the standard method for fetal well-being surveillance used during labor and delivery. There are, however, situations when tracings displayed by the EFHM are ambiguous and misleading. We present two cases where the Maternal Heart Rate (MHR) artefacts were mistaken for Fetal Heart Rate (FHR). In the first case, MHR masked the severity of fetal distress and caused a delayed and inappropriate management with subsequent poor neonatal outcome. In the second case, MHR was misinterpreted as FHR causing embarrassment of the birth attendants upon delivery of a dead macerated newborn. FHR should initially and continuously be verified as the actual origin of the signal displayed on the EFHM before any intervention is undertaken. Understanding the EFHM patterns produced by FHR or MHR and the utilization of modern EFHMs that apply concomitant recording and displaying of MHR and FHR can avert problems associated with signal ambiguity.