Imperative for improvements and international convergence of intrapartum fetal monitoring: A bird’s eye view

Abstract

Intrapartum fetal monitoring has been criticized for the lack of evidence of improvement in fetal outcome despite causing increased operative intervention. Paradoxically, cardiotocography (CTG) has been a major driver for litigation for neonatal neurological injury. This analytical review tries to explore why extensive clinical studies and trials over 50 years have failed to demonstrate or bring about significant improvement in intrapartum fetal monitoring. There seems a need for significant reform. International congruence on most aspects of CTG interpretation [definitions of fetal heart rate (FHR) parameters, CTG recording speed, 3-tier systems, etc.] is highly desirable to facilitate future meaningful clinical studies, evaluation and progress in this field. The FHR changes are non-specific and poor surrogate for fetal well-being. As a compromise for maintaining low false-negative results for fetal acidemia, a high false-positive value may have to be accepted. The need for redefining the place of adjuvant tests of fetal well-being like fetal blood sampling or fetal electrocardiography (ECG) is discussed. The FHR decelerations are often deterministic (center-stage) in CTG interpretation and 3-tier categorization. It is discussed if their scientific and physiological classification (avoiding framing and confirmation biases) may be best based on time relationship to uterine contractions alone. This may provide a more sound foundation which could improve the reliability and further evolution of 3-tier systems. Results of several trials of fetal ECG (STAN) have been inconclusive and a need for a fresh approach or strategy is considered. It is hoped that the long anticipated Computer-aided analysis of CTG will be more objective and reliable (overcome human factors) and will offer valuable support or may eventually replace visual CTG interpretation. In any case, the recording and archiving all CTGs digitally and testing cord blood gases routinely in every delivery would be highly desirable for future research. This would facilitate well designed retrospective studies which can be very informative especially when prospective randomised controlled trials are often difficult and resource-intensive.

Keywords: Cardiotocography, Electronic fetal monitoring, Fetal heart rate decelerations, Intrapartum fetal monitoring, Intrapartum fetal surveillance, Fetal electrocardiography, Computerised cardiotocography

Core tip: Intrapartum fetal monitoring remains unsatisfactory because of the variability and errors in the interpretation of cardiotocographs and lack of proven benefit. Extensive clinical studies over the last 50 years have given divergent results because of the heterogeneity. There is a need for a significant reform of electronic fetal monitoring (EFM) with every aspect critically examined and debated. This analytical essay presents an overview of the current and newer modalities of EFM. It examines controversies and opportunities for improvement in American and European practice. Avoidance of biases, international congruence in terminology/standardization and refinement of adjunctive tests of fetal well-being are explored.