Re-conceptualizing fetal monitoring

Abstract

Electronic fetal monitoring (EFM) has been used extensively in labor for over 40 years despite its appreciated failure to identify, in a timely fashion, and help prevent a large proportion of cases of neonatal encephalopathy and cerebral palsy. Our analysis suggests that the poor performance of EFM derives from a fundamental misunderstanding of the differences between screening and diagnostic tests, large inter-observer variability in its interpretation as a result of very subjective classifications, failure to follow the physiology of fetal compromise, and poor statistical modeling for its use as a screening test. We have recently developed a new methodology, the fetal reserve index (FRI) which contextualizes the interpretation of EFM by 1. breaking EFM down into four components: heart rate, variability, accelerations, and decelerations; and then 2. adding increased uterine activity, and 3. risk factors (maternal, fetal, and obstetrical) to create an 8-point algorithm. In a direct comparison of the ACOG monograph criteria, ACOG Category system and the FRI, the FRI performed much better in identifying cases at risk before damage had occurred, and reduced both the need for emergency deliveries and overall Cesarean delivery rates.