Intrapartum Evaluation of the Fetus

In 1958, the introduction of electronic fetal monitoring (EFM) dramatically changed labor and delivery practices by aiming to detect fetal heart rate (FHR) changes that could indicate fetal acidosis and prevent perinatal asphyxia. However, despite widespread adoption and numerous randomized controlled trials (RCTs) over the years, EFM has not demonstrated a significant impact on perinatal morbidity and mortality. Studies highlighted the minimal predictive value of nonreassuring FHR patterns for outcomes like cerebral palsy, alongside a high false positive rate. Critics argue that EFM may lead to an overdetection of nonreassuring patterns, contributing to the rising cesarean delivery rates in the United States. This chapter reviews the physiological basis of FHR patterns, the limitations of current monitoring practices, and explores ancillary tests that may enhance diagnostic accuracy. Additionally, it discusses the advancements in fetal ECG, pulse oximetry, and emerging machine learning technologies that could improve fetal assessment during labor.