Introduction
Electronic foetal monitoring was invented in the 1960s, and cardiotocography (CTG) has since become the primary means of monitoring foetal well-being during labour in developed countries1,2. CTG interpretation has an excellent negative predictive value but carries the drawback of a mediocre positive predictive value3. Thus, the interpretation of an abnormal CTG is challenging, and misinterpretations are frequent with the implicit risk of performing excessive foetal extractions or conversely, to wrongly abstain from an intervention that would have been necessary to preserve foetal well-being4,5. CTG is therefore an imperfect tool to be used alone to make decisions with potentially serious consequences, often in emergency situations. In this context, second-line methods have found their use in cases of abnormal CTG and they allow us to differentiate abnormalities that reflect foetal acidosis from those that do not have an impact on foetal well-being6.
This rationale has recently been challenged. Some authors have suggested that foetal monitoring does not inherently have a low positive predictive value and that its diagnostic performance could be improved by a paradigm shift in its interpretation7. Their claim is that CTG should not be interpreted on a pattern recognition basis but with a pathophysiological approach instead8–10. Indeed, traditionally, the interpretation of the CTG is taught by learning distinct criteria of concern (baseline heart rate, absence of accelerations, short-term variability, presence of decelerations) and by the recognition of different patterns of decelerations (early, variable or late; typical or atypical)11. The new paradigm is based on pathophysiology studies, especially in animals, and promotes the teaching of explanations of the foetal response to various phenomena occurring during labour8,12. One of the main purposes of this method is to differentiate between tracings that correspond to a physiological adaptation of the foetus and those that have a decompensatory meaning and require immediate foetal extraction. The underlying implicit goal is to sufficiently improve the positive predictive value of the CTG interpretation to dispense with second-line methods13–15. Since 2017 and the publication of the ”Handbook of CTG Interpretation: From Patterns to Physiology”, this method of interpretation has been widely promoted, particularly through specific training courses8. However, there are no existing studies to determine the value of these teachings on clinical decision-making.
The objective of this study was to evaluate the impact of specific training in CTG physiology-based interpretation on professional attitudes towards the use of second-line methods.