Interpretation
The underlying goal of physiology-based CTG interpretation is to dispense with second-line methods14,15. In a 2014 insightful review, Edwin Chandraharan pointed out the absence of evidence supporting foetal scalp blood sampling during labour13. This critique was brilliantly enriched with a detailed list of pathophysiological inconsistencies associated with the use of this test; in particular, a sample of blood from nonessential peripheral tissue (foetal scalp) is being used to assess the acid–base status of essential central organs. His conclusion was that foetal scalp blood sampling was an outdated practice and that it should no longer be recommended. This review provoked a debate among various authors whose responses were just as interesting as the original article, essentially discussing the pathophysiological basis of foetal scalp blood sampling16–18. These expert debates are enlightening, but no pathophysiological analysis can ever replace the evidence provided by a well-conducted clinical study. Since 2014, despite this article, which should have encouraged research on this matter, little has been done to demonstrate the usefulness of second-line methods, which are still widely used despite this lack of evidence.
The same reasoning could easily be applied to physiology-based CTG interpretation training. There is no doubt that pathophysiological teaching leads to a deeper understanding of medical phenomena and should be encouraged. Recent studies showed that training programmes based on foetal physiology led to a long-term improvement in CTG interpretation and to homogenization of obstetrical decisions in simulated situations19,20. However, there is a strong need for clinical evidence regarding the teaching of this method before totally discouraging second-line methods. As suggested by our results, overconfidence in the interpretation of CTG could lead to wrong decisions and it should therefore be taught with humility and by stressing the importance of being cautious when in doubt. The present article is up to date and, to our knowledge, is the only attempt to analyse the effect of physiology-based CTG interpretation training on obstetrical practice. Although our work is clearly insufficient on its own to substantiate the benefits or shortcomings of this teaching, it does have the merits of raising the issue of the lack of evidence and should encourage further research.