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.