What actions should be taken in response to a color change in Fetal Heart Rate (FHR) tracings during labor?

From the Guidelines

When a color change occurs in Fetal Heart Rate (FHR) tracings during labor, immediate assessment and intervention are necessary to prevent potential fetal hypoxia and improve outcomes. The color change is typically an indication of a concerning pattern, such as late decelerations or bradycardia, which may suggest fetal distress 1. Initial interventions should include:

• Maternal repositioning to the left lateral position to improve uteroplacental perfusion
• Administration of supplemental oxygen at 8-10 L/min via face mask
• Discontinuation of oxytocin if it's being administered
• Provision of IV fluid bolus of 500-1000 mL of lactated Ringer's solution to improve maternal volume status
• Administration of vasopressors such as ephedrine 5-10 mg IV or phenylephrine 50-100 mcg IV for hypotension

These actions address the underlying causes of abnormal FHR patterns, which often relate to uteroplacental insufficiency, cord compression, or maternal hypotension 1. The goal is to improve fetal oxygenation and prevent potential hypoxic injury while preparing for expedited delivery if necessary. According to the National Institute of Child Health and Human Development (NICHD) guidelines, a three-category system is used to classify FHR tracings: normal (category I), indeterminate (category II), and abnormal (category III) 1. Category III tracings require immediate intervention to resolve the abnormal tracing or to expedite delivery. The DR C BRAVADO approach can be used to systematically interpret FHR tracings, taking into account maternal and fetal risk factors, contractions, and fetal monitor strip findings 1.

Key elements to consider when interpreting FHR tracings include:

• Baseline heart rate
• Presence or absence of variability
• Interpretation of periodic changes
• Overall assessment of the tracing

By following these guidelines and taking prompt action in response to concerning FHR patterns, healthcare providers can help improve fetal outcomes and reduce the risk of complications during labor 1.

From the Research

Fetal Heart Rate Tracings in Labor

• Fetal heart rate (FHR) tracings are used to monitor the well-being of the fetus during labor, with changes in the tracing indicating potential fetal distress or compromise 2.
• The FHR signal may change color in response to various factors, including mechanical and hypoxic stresses, which can occur during labor due to uterine contractions, umbilical cord compression, or reduced uteroplacental oxygenation 2.

Interpretation of FHR Tracings

• Traditional classification systems for FHR interpretation during labor group certain features of FHR into different categories, such as category I, II, and III tracings, or "normal, suspicious, and pathologic" 2.
• However, these systems have limitations, as they do not account for individual fetal reserves and compensatory responses, and may not accurately reflect the fetal condition 2.
• A pathophysiological interpretation of FHR tracings, taking into account the clinical context and features suggestive of fetal compromise, is essential for accurate assessment and management of fetal well-being during labor 2.

Actions in Response to Color Change in FHR Tracings

• If a color change is observed in the FHR tracing, indicating potential fetal distress or compromise, various actions can be taken to improve fetal well-being, including:
  • Intrauterine resuscitation techniques, such as left lateral recumbent positioning, rapid intravenous infusion of crystalloid, maternal oxygen administration, and inhibition of uterine contractions with terbutaline 3.
  • Preparation for emergency delivery, such as cesarean section, if the fetal condition does not improve with intrauterine resuscitation 4, 3.
  • Administration of terbutaline to inhibit uterine contractions and improve fetal well-being, although this should be regarded as a temporary measure until the fetal heart rate recovers 4, 5.

Clinical Significance of Abnormal FHR Patterns

• Abnormal FHR patterns during labor, including late decelerations, bradycardia, and variable decelerations, can be associated with fetal acidosis and adverse pregnancy outcomes 6.
• The presence of abnormal FHR patterns during the second stage of labor is independently associated with fetal acidosis, and expedited delivery should be considered in these cases 6.