Chapter 18 Fetal Assessment During Labor Copyright © 2016 by Elsevier Inc. All rights reserved.

Learning Objectives Identify typical signs of normal and abnormal fetal heart rate (FHR) patterns. Compare FHR monitoring performed by intermittent auscultation with external and internal electronic methods. Explain the baseline FHR and evaluate periodic changes. Describe nursing measures that can be used to maintain FHR patterns within normal limits. Differentiate among the nursing interventions used for managing specific FHR patterns, including tachycardia and bradycardia, absence of or minimal variability, and late and variable decelerations. Review the documentation of the monitoring process necessary during labor.

Basis for Monitoring Fetal response Oxygen supply must be maintained to prevent fetal compromise. Decrease in oxygen supply due to: Reduction of blood flow through maternal vessels Reduction in oxygen content in maternal blood Alterations in fetal circulation Reduction in blood flow to intervillous space in placenta

Basis for Monitoring (Cont.) Uterine activity: Monitoring provides information on uterine contractions. Fetal compromise: The goals of intrapartum FHR monitoring are to identify and differentiate the normal (reassuring) patterns from the abnormal (nonreassuring) patterns, which can be indicative of fetal compromise.

Monitoring Techniques Intermittent auscultation Listening to fetal heart sounds at periodic intervals to assess FHR Easy to use, inexpensive, less invasive than EFM Difficult to perform on women who are obese Does not provide a permanent record Electronic fetal monitoring External monitoring Ultrasound transducer Toco transducer (tocodynamometer) Monica AN24: Introduced in 2011; 5 electrodes on woman; information transmitted via Bluetooth

Monitoring Techniques (Cont.)

Monitoring Techniques (Cont.) Electronic fetal monitoring (Cont.) Internal monitoring Spiral electrode Intrauterine pressure catheter (IUPC) Display: displayed on the monitor paper or computer screen, with the FHR in the upper section and UA in the lower section

Fetal Heart Rate Patterns Baseline fetal heart rate Average rate during a 10-minute segment that excludes: Periodic or episodic changes Periods of marked variability Segments of the baseline that differ by more than 25 beats/min There must be at least 2 minutes of interpretable data

Fetal Heart Rate Patterns (Cont.) Baseline fetal heart rate (Cont.) Variability Described as irregular waves or fluctuations in the baseline FHR of two cycles per minute or greater 4 possible categories of variability: Absence Minimal Moderate Marked

Fetal Heart Rate Patterns (Cont.) Tachycardia: >160 beats/min  10 minutes or more Bradycardia: <110 beats/min  10 minutes or more Changes in FHR Periodic changes occurring with UCs Episodic (nonperiodic changes) not associated with UCs Accelerations Considered an indication of fetal well-being

Fetal Heart Rate Patterns (Cont.)

Fetal Heart Rate Patterns (Cont.) Changes in FHR (Cont.) Decelerations Early decelerations in response to fetal head compression Late decelerations due to uteroplacental insufficiency Variable decelerations due to umbilical cord compression Prolonged decelerations

Fetal Heart Rate Patterns (Cont.)

Fetal Heart Rate Patterns (Cont.)

Fetal Heart Rate Patterns (Cont.)

Fetal Heart Rate Patterns (Cont.)

Fetal Heart Rate Patterns (Cont.)

Fetal Heart Rate Patterns (Cont.)

FHR Monitoring: Care Management EFM pattern recognition and interpretation NICHD Workshop 2008 proposed a three-tier system for EFM interpretation Category I: normal Category II: indeterminate Category III: abnormal Fetal monitoring standards Nursing management of nonreassuring patterns

Fetal Heart Rate Categories Normal FHR patterns described as reassuring Category I Baseline FHR in the normal range of 110-160 beats/min Baseline fetal heart rate variability: moderate Late or variable decelerations: absent Early decelerations: may be present or absent Accelerations: either present or absent (ACOG Practice Bulletin 2009) 22

Fetal Heart Rate Categories (Cont.) Indeterminate FHR patterns Category II Bradycardia not accompanied by absence of baseline variability Tachycardia Minimal or absence of baseline variability not accompanied by recurrent decelerations Marked baseline variability No accelerations in response to fetal stimulation Periodic or episodic decelerations

Fetal Heart Rate Categories (Cont.) Abnormal FHR patterns described as nonreassuring Category III Nonreassuring FHR patterns associated with fetal hypoxemia Hypoxemia can deteriorate to severe fetal hypoxia Absence of baseline variability Recurrent or late decelerations Bradycardia Sinusoidal pattern

FHR Monitoring: Care Management Nursing management of abnormal patterns The five essential components of the FHR tracing that must be evaluated regularly are baseline rate, baseline variability, accelerations, decelerations, and changes or trends over time. If any component is abnormal, corrective measures must be taken immediately to improve fetal oxygenation: intrauterine resuscitation Supplemental oxygen Maternal position changes Increasing intravenous fluids

FHR Monitoring: Care Management (Cont.) Other methods of assessment and interventions Fetal scalp stimulation and vibroacoustic stimulation Umbilical cord acid-base determination Fetal scalp blood sampling Amnioinfusion Tocolytic therapy

Key Points Fetal well-being during labor is gauged by the response of the FHR to UCs. Standardized definitions for many common FHR patterns have been adopted for use in clinical practice by the ACNM, ACOG, and AWHONN. The five essential components of the FHR tracing are baseline rate, baseline variability, accelerations, decelerations, and changes or trends over time.

Key Points (Cont.) The monitoring of fetal well-being includes FHR and UA assessment and assessment of maternal vital signs. The FHR can be monitored by either IA or EFM. The FHR and UA can be assessed by EFM using either the external or internal monitoring mode. Assessing FHR and UA patterns, implementing independent nursing interventions, and reporting abnormal patterns to the physician or nurse-midwife are the nurse’s responsibilities.

Key Points (Cont.) The AWHONN and ACOG have established and published health care provider standards and guidelines for FHR monitoring. The emotional, informational, and comfort needs of the woman and her family must be addressed when the mother and her fetus are being monitored. Documentation of fetal assessment is initiated and updated according to institutional protocol.

Question While evaluating an external monitor tracing of a woman in active labor whose labor is being induced, the nurse notes that the fetal heart rate (FHR) begins to decelerate at the onset of several contractions and returns to baseline before each contraction ends. The nurse should: Change the woman’s position Discontinue the oxytocin infusion Insert an internal monitor Document the finding in the client’s record ANS: D Feedback A Incorrect: The FHR indicates early decelerations, which are not an ominous sign and do not require any intervention. The nurse should simply document these findings. B Incorrect: It is inappropriate for the nurse to discontinue the oxytocin infusion at this time. The presence of early decelerations is not an ominous sign and does not require any intervention. C Incorrect: The presence of early decelerations is not an ominous sign and does not require any intervention. It is unnecessary for the nurse to insert an internal monitor. D Correct: The FHR indicates early decelerations, which are not an ominous sign and do not require any intervention. The nurse should simply document these findings.