Learning Objectives
By the end of this section, you will be able to:
- Explain the nursing interventions for abnormal fetal heart rate baseline
- Explain the nursing interventions for abnormal fetal heart rate variability
- Explain the nursing interventions for fetal heart rate decelerations
- Explain the nursing interventions based on the three-tiered system for FHR interpretation
The FHR monitor allows the nurse to assess the health of the fetus and how the fetus is tolerating labor. The nurse needs to recognize whether the fetal monitor tracing indicates a well-oxygenated fetus or a fetus in distress. Fetal distress can be caused by a number of factors; therefore, determining the cause of the abnormality shown on the tracing is paramount. The nurse needs to use specific interventions aimed at correcting those causes.
Nursing Interventions for Abnormal Fetal Heart Rate Baseline
The FHR baseline is a reliable indicator of fetal oxygenation. One of the most reliable signs of adequate fetal oxygenation is an FHR baseline between 110 and 160 bpm with moderate variability. Changes in the FHR baseline can be caused by medications administered to the pregnant patient during labor, such as pain management narcotics, magnesium sulfate, and terbutaline. These baseline changes will resolve after the medication has been discontinued or excreted. Nursing intervention is often not necessary, but any changes should be monitored closely. Changes in the FHR baseline that do require nursing intervention are fetal bradycardia and tachycardia.
Fetal Bradycardia
Fetal bradycardia is an FHR baseline of <110 bpm lasting more than 10 minutes. Bradycardia is abnormal and must be addressed urgently. The nurse must determine the cause of the bradycardia and tailor the intervention to that cause. The cause of bradycardia may be evident, as in the case of a prolapsed umbilical cord that is seen on observation. The nursing intervention for a prolapsed cord is to insert two fingers into the vagina (avoiding the umbilical cord), locate the presenting part, and elevate the presenting part away from the umbilical cord to resolve the cord compression and allow return of blood flow. The nurse must hold this position until the fetus is delivered via cesarean birth. Similarly, placental abruption and uterine rupture can cause hemorrhaging that is concealed but demonstrated through the interpretation of the FHR and UC pattern; these conditions require immediate delivery via cesarean birth.
Uterine tachysystole can cause fetal bradycardia. The lack of time for fetal recovery between contractions uses up fetal reserve. When this reserve is depleted, fetal bradycardia occurs. The nurse will discontinue oxytocin, if in use, and administer a tocolytic medication such as terbutaline. The tocolytic medication relaxes the uterus, allowing return of placental blood flow to the fetus.
Some covert causes of fetal bradycardia may require multiple interventions to determine the cause and resolve the issue. The first nursing intervention is repositioning the laboring person, unless oxytocin is being used; in that case, discontinuing oxytocin is necessary. The second intervention is to perform a cervical exam to assess for a prolapsed cord or rapid descent of the fetal head. If these interventions do not resolve the bradycardia, the nurse will immediately notify the health-care provider while continuing to evaluate causes and initiating intrauterine resuscitation, discussed later in the chapter.
Fetal Tachycardia
Fetal tachycardia is an FHR baseline over 160 bpm and is considered an abnormal finding. The cause of the tachycardia will dictate the nursing intervention. The most common cause of fetal tachycardia is fever in the pregnant person. If the pregnant patient exhibits a temperature of greater than 100.4° F (38° C), the nurse notifies the health-care provider so that they can determine which medical intervention to initiate. Antibiotics and antipyretics are common pharmaceutical interventions to treat fever and infection.
Epidural anesthesia can cause a minimal rise in temperature in the laboring person. Research has shown that epidural anesthesia can induce inflammatory responses that produce fever (Khanna et al., 2020). Epidural anesthesia can also affect the thermoregulatory system, causing shivering that, in turn, causes elevated temperature.
Dehydration, anemia, or hyperthyroidism can all cause fetal tachycardia. To limit the risk of dehydration, the nurse monitors the intake and output of the laboring person. If dehydration is apparent, the nurse will either encourage oral hydration or initiate an intravenous fluid bolus. The nurse can also review the history to determine if anemia or hyperthyroidism was noted during prenatal care.
Fetal heart rate tachycardia is associated with prematurity and caused by fetal stress (especially in prolonged labor), infection, hypoxia, anemia, or prolonged stimulation. If oxytocin is being administered, discontinuation of the oxytocin infusion may be indicated. If this does not resolve the tachycardia, the nurse will contact the health-care provider, describe the FHR tracing, and receive orders for further management.
Nursing Interventions for Abnormal Fetal Heart Rate Variability
FHR baseline variability is a very important characteristic for evaluating fetal well-being. As previously discussed, variability is the best determinant of fetal oxygenation. Therefore, determining the cause of altered variability is imperative to restoring fetal oxygenation. Pharmacologic causes of decreased variability can be pain-relieving narcotics, cocaine, corticosteroids, and magnesium sulfate administered to the laboring person. Administration of butorphanol (Stadol) can cause a sinusoidal pattern. These causes are transient and not pathologic. Changes caused by these medications will resolve once the medication is excreted, and no nursing intervention is warranted.
Marked FHR baseline variability is rare. The most common time for marked variability is during the 2 hours prior to delivery (Polnaszek et al., 2020). Marked variability is usually seen after an event of decreased fetal oxygenation, such as a seizure of the pregnant person or cord compression, and it is associated with an increased risk for neonatal respiratory distress after birth (Polnaszek et al., 2020). The nursing intervention for marked variability is to prevent seizure and quickly provide oxygen after any seizure that occurs. If cord compression is present, the nurse resolves the cord compression and again provides oxygen to the laboring person.
Nursing Interventions for Fetal Heart Rate Decelerations
Knowing the causes of each type of FHR deceleration can guide the nurse to intervene appropriately. Table 16.5 describes the nursing interventions for each type of FHR deceleration.
| Type of Deceleration | Cause | Intervention |
|---|---|---|
| Variable | Cord compression Oligohydramnios |
|
| Early | Fetal head compression Fetal vagal response |
|
| Late | Uteroplacental insufficiency |
|
| Prolonged | Cord compression Uteroplacental insufficiency Fetal hemorrhage Fetal vagal reaction Fetal CNS anomalies |
|
Nursing Interventions Based on the Three-Tiered System for Fetal Heart Rate Interpretation
The National Institute of Child Health and Human Development Working Group developed a three-tiered classification to interpret FHR patterns (ACOG, 2009). The adoption of the three categories for fetal monitoring has allowed all health-care providers to systematically describe fetal monitor tracings as well as consistently manage abnormal tracings (see Figure 16.25).
On the basis of the tiered system, the nurse interprets the category of FHR tracing and determines the need for intervention. When fetal distress is identified, the nurse begins interventions to correct the cause of the insult and notifies the health-care provider of the incident. Category I tracings are normal and do not require interventions. Category II tracings are more difficult when creating a management plan. These tracings do not meet criteria for either normal or pathologic tracings. The nurse must evaluate for FHR accelerations and baseline variability. If the FHR baseline is without accelerations or moderate variability, the nurse will begin intrauterine resuscitation. Category II tracings that do not respond to intrauterine resuscitation become Category III. Category III tracings imply fetal hypoxia. Intrauterine resuscitation should be started, and birth should be expedited.
Legal and Ethical Issues
What Happens When Interventions Do Not Occur in Response to FHR Tracings?
Fetal heart rate monitoring provides nurses and health-care providers with information to ensure the safety of the fetus and the laboring person. When the fetal heart rate tracing is nonreassuring, interventions should occur to resolve the cause of the abnormal tracing. In cases where interventions are not initiated, fetal safety can be jeopardized, leading to fetal hypoxic injuries; at other times the fetus recovers without the intervention. Despite the outcome of the fetus, this incident should be evaluated for quality improvement. Nurses, health-care providers, and hospital staff should meet to discuss factors that could have influenced the situation, such as staffing issues or technical problems with monitoring. This process of quality improvement is not to determine fault. The process is used to analyze the influencing factors and create a plan to avoid the mistake in the future. Nurses play an integral role in quality improvement.