Chapter 17: Intrapartum Fetal Surveillance

The physiological foundation emphasizes fetal oxygenation mechanisms, including maternal blood flow delivery, placental gas exchange efficiency, and patency of umbilical circulation. Pathological conditions such as maternal hypotension, excessive uterine contractions, or placental abruption can disrupt this oxygen supply chain and compromise fetal status. Fetal heart rate regulation occurs through autonomic nervous system control via baroreceptors and chemoreceptors, with sympathetic and parasympathetic interactions creating the characteristic baseline variability observed during monitoring. The chapter compares intermittent auscultation, a low-technology approach using fetoscope or Doppler ultrasound, with electronic fetal monitoring, a high-technology method employing external transducers or internal devices such as fetal scalp electrodes and intrauterine pressure catheters for enhanced precision. Comprehensive interpretation guidelines address baseline heart rate categories including bradycardia, normality, and tachycardia alongside variability assessment ranging from absent to marked patterns and analysis of periodic changes. Accelerations indicate reassuring fetal nervous system function, while decelerations are classified by mechanism: early decelerations reflect head compression, late decelerations suggest placental insufficiency, and variable decelerations result from cord compression events. The National Institute of Child Health and Human Development interpretation framework categorizes tracings into three tiers—Category I representing normal findings, Category II indicating indeterminate patterns requiring further evaluation, and Category III reflecting abnormal or nonreassuring status necessitating intervention. Essential nursing responses to nonreassuring patterns involve intrauterine resuscitation strategies including maternal repositioning, intravenous fluid administration, oxytocin discontinuation, and supplemental oxygen delivery. The chapter also reviews adjunctive assessment methods such as fetal scalp stimulation, vibroacoustic stimulation, amnioinfusion procedures, and umbilical cord blood gas analysis to determine fetal acid-base status and guide appropriate clinical decision-making.