Evolving Frameworks for the Foundation and Practice of Electronic Fetal Monitoring

Abstract

Since the 1970s, electronic fetal monitoring (EFM) also known as cardiotocography (CTG) has been used extensively in labor around the world, despite its known failure to help prevent many babies from developing neonatal encephalopathy and cerebral palsy. Part of EFM's poor performance with respect to these outcomes arises from a fundamental misunderstanding of the differences between screening and diagnostic tests, subjective classifications of fetal heart rate (FHR) patterns that lead to large inter-observer variability in its interpretation, failure to appreciate early stages of fetal compromise, and poor statistical modeling for its use as a screening test. We have developed a new approach to the practice and interpretation of EFM called the fetal reserve index (FRI) which does the following: (1) breaking FHR components down into 4 components, (heart rate, variability, accelerations, and decelerations); (2) contextualizing the metrics by adding increased uterine activity; (3) adding specific maternal, fetal, and obstetric risk factors. The result is an eight-point scoring metric that, when directly compared with current American College of Obstetricians and Gynecologists EFM categories, even in version 1.0 with equal weighting of variables, shows that the FRI has performed much better for identifying cases at risk before damage had occurred, reducing the need for emergency deliveries, and lowering overall Cesarean delivery rates. With increased data, we expect further refinements in the specifics of scoring that will allow even earlier detection of compromise in labor.

Resistance to Change

“…Of course, the majority of methods to achieve such never see the light of day, thus allowing for sometimes egregious commentaries to go unchallenged. As an example, over the past several years, our own work has focused on developing a new approach to EFM [101][102][103][104][105][106][107][108][109][110][111][112][113]. It has attacked the very poor performance metrics for EFM that even its own key opinion leaders admit and essentially proposed that various kinds of risk factors and uterine contraction frequency be used to contextualize EFM data and expand the clinical utility of EFM-based predictive models [114][115][116].…”

“…The unifying theme to all these criticisms is that they lead to the primary rejection of the papers with no opportunity to respond to even absurd criticisms. All these papers were eventually published by other reputable journals [101][102][103][104][105][106][107][108][109][110][111][112][113]. If they are looking for it, editors and experienced reviewers can usually distinguish between a legitimate review and "hit jobs."…”

Implications of Genetic Variants in Cerebral Palsy

“…Our own work has focused on improving interpretation of electronic fetal monitoring through a developing metric (the Fetal Reserve Index) to improve care and reduce risks . Our assessment suggests that about one-third of CP cases are likely of genetic origin, a calculation virtually identical to that of Gonzalez-Mantilla. However, these estimates will not satisfy either side in the medicolegal arena.…”