16.1 Basic Terms of Fetal Heart Rate and Contraction Patterns
The nurse uses the FHR to determine the well-being of the fetus during the antepartum and intrapartum periods by evaluating for FHR baseline variability, accelerations, and decelerations. A reassuring FHR tracing demonstrates adequate oxygenation and includes moderate variability, accelerations, and a baseline FHR between 110 and 160 bpm. An FHR tracing can also show signs of fetal compromise and hypoxia. Signs of a nonreassuring FHR tracing include minimal or absent variability, late decelerations, marked variability, and prolonged decelerations. Nurses in the perinatal area are trained and can be certified in FHR monitoring. Training in FHR and contraction monitoring allows nurses to safely care for the laboring person and fetus.
16.2 External and Internal Monitoring
Fetal monitoring can be performed using intermittent or continuous methods, with monitoring devices applied externally or internally. The nurse is aware of the advantages and disadvantages of each type of monitoring technique. The specific needs of the pregnant person and fetus should guide the health-care team in choosing the type of monitoring used.
The nurse uses the information gleaned from the fetal monitor to evaluate and determine if interventions should be initiated. The three-tiered category of interpretation standardizes FHR terminology and guides the actions of the provider and nurse. Standardized terminology also aids in documentation of the interpretation of the FHR and UC. Nurses play a vital role in assessing the health of the fetus and pregnant person in the antepartum and intrapartum periods.
16.3 Physiological Influences on Fetal Heart Rate Patterns
Physiologic changes can affect the FHR and are associated with abnormalities in the FHR tracings. Uteroplacental insufficiency and damage to the fetal nervous system can be recognized as minimal to absent FHR variability with late or prolonged decelerations. Fetal cardiac abnormalities can cause FHR tracings with FHR baseline spiking and bradycardia. The fetus can compensate for these changes for a time. Once the fetal reserve is depleted, the fetus can no longer compensate and is in danger of neurologic injury or death. The nurse is aware of the importance of these physiologic changes and the need to intervene when observing these FHR tracings.
16.4 Nursing Interventions Based on Fetal Heart Rate and Uterine Contraction Patterns
The nurse interprets FHR tracings and determines the oxygenation of the fetus based on these tracings. The FHR baseline is an important component of fetal monitor tracing. Changes in the FHR baseline can be seen as bradycardia and tachycardia. FHR baseline variability is another component used to determine fetal well-being. FHR baseline variability that is absent or marked can show signs of fetal hypoxia. Periodic changes, such as FHR decelerations, are abnormal and assessed for need of intervention. The nurse uses all these components to determine which of the three fetal monitoring categories the tracing belongs to. The nurse then initiates interventions to resolve nonreassuring FHR tracings. The nurse is responsible for ensuring that proper interventions are initiated to protect the fetus.
16.5 Intrauterine Resuscitation
Intrauterine resuscitation is often successful in restoring oxygen to the fetus. The nurse is aware of the steps of intrauterine resuscitation and of the FHR abnormalities that respond to resuscitation, such as late or prolonged declarations and minimal to absent variability. Intrauterine resuscitation can resolve uteroplacental insufficiency, allowing the fetus to return to a well-oxygenated state.