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CC BY-NC-ND 4.0 · AJP Rep 2020; 10(03): e342-e345
DOI: 10.1055/s-0040-1713786
Original Article

Bayes Theorem and Protopathic Bias: Methodological Concerns When Addressing the Impact of Fetal Heart Rate Patterns on the Cesarean Section Rate

Jacques Balayla
1   Department of Obstetrics and Gynecology, McGill University, Montreal, Quebec, Canada
,
Ariane Lasry
1   Department of Obstetrics and Gynecology, McGill University, Montreal, Quebec, Canada
,
Yaron Gil
1   Department of Obstetrics and Gynecology, McGill University, Montreal, Quebec, Canada
,
Alexander Volodarsky-Perel
1   Department of Obstetrics and Gynecology, McGill University, Montreal, Quebec, Canada
› Author Affiliations Funding No funding was received for this study.
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Abstract

Over the last 30 years, the caesarean section rate has reached global epidemic proportions. This trend is driven by multiple factors, an important one of which is the use and inconsistent interpretation of the electronic fetal monitoring (EFM) system. Despite its introduction in the 1960s, the EFM has not definitively improved neonatal outcomes, yet it has since significantly contributed to a seven-fold increase in the caesarean section rate. As we attempt to reduce the caesarean rates in the developed world, we should consider focusing on areas that have garnered little attention in the literature, such as physician sensitization to the poor predictive power of the EFM and the research method biases that are involved in studying the abnormal heart rate patterns—umbilical cord pH relationship. Herein, we apply Bayes theorem to different clinical scenarios to illustrate the poor predictive power of the EFM, as well as shed light on the principle of protopathic bias, which affects the classification of research outcomes among studies addressing the effects of the EFM on caesarean rates. We propose and discuss potential solutions to the aforementioned considerations, which include the re-examination of guidelines with which we interpret fetal heart rate patterns and the development of noninvasive technologies that evaluate fetal pH in real time.

Keywords

fetal pH - caesarean section - Bayes theorem - protopathic bias


Publication History

Received: 03 March 2020

Accepted: 09 April 2020

Article published online:
23 September 2020

© 2020. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).

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