Fetal Monitoring Basics Expanded NUR 231 M. Johnston, RN-BC, M.Ed. Cindy Irwin , RNC, MN

Types of Monitoring Auscultation- listen to fetal heart rate (FHR) Electronic Fetal Monitoring – use of instruments to record FHR and uterine contractions(U/Cs)

Auscultation Doppler - ultrasound converts sounds waves to signals of fetal heart Fetoscope - Like stethoscope, open end pressed on abdomen, used less frequently

Electronic Fetal Monitoring Measures response of FHR to uterine contractions (U/Cs) Intermittent or Continuous External Ultrasound transducer Tocotransducer Internal Fetal Scalp Electrode Intrauterine Pressure Catheter

Fetal Monitoring Setup

Fetal Heart Rate Characteristics Evaluate to determine fetal status NICHD terminology Baseline Rate Baseline Variability Accelerations (present or absent) Decelerations (present or absent) Changes or trends over time

Baseline (BL) Normal range 110-160 bpm Measure between U/Cs for at least 2 min. period during 10 minute segment Tachycardia - >160 bpm for >10 minutes Bradycardia - <110 bpm for >10 minutes

Baseline

Classifications of FHR Variability Fluctuations in FHR, irregular in frequency and amplitude Absent 0-2 bpm Minimal >2 <6 bpm Moderate 6 -25 bpm Marked >25 bpm

Absent Variabilty

Minimal Variability

Moderate Variability

Marked Variability

Periodic/Episodic Changes Periodic with uterine contractions Episodic without uterine contractions

Accelerations Abrupt increase in FHR above BL Present or Absent < 32 wks gestation Peak ≥ 10 bpm above BL for at least 10 sec. >32 wks gestation Peak ≥ 15 bpm above BL for at least 15 sec. Accel ≥ 10 min. is defined as BL change

Accelerations Abrupt increase in FHR above BL Peak ≥ 15 bpm above BL for at least 15 sec. Increase in FHR with fetal activity, just like adult HR increases with exercise At times, fetus moves in response to U/Cs A sign of fetal well-being

Recognition Criteria for Fetal Heart Rate Accelerations Transient increase in the Fetal Heart Rate > 32 weeks acceleration stays 15 beats above the baseline for at least 15 seconds < 32 weeks acceleration stays 10 beats above the baseline for at least 10 seconds

Types of Decelerations Early – Gradual decrease and return to BL, mirrors the U/C Variable – Abrupt (<30 sec) decrease (≥15 sec down, lasting ≥ 15 sec and <2 min from onset to return to BL) Late – Gradual decrease (≥30 sec) and gradual return to BL; delayed timing nadir occurs after peak of U/C Prolonged – Decrease in FHR below BL ≥15 sec, lasting ≥ 2 min. but <10 min.

Early Deceleration Gradual decrease and return to BL Mirrors the U/C

Early Deceleration

Early Decelerations Usually benign May be associated with descent of fetus Monitor to assure fetal well-being, no evidence of worsening condition

Variable Deceleration Abrupt (<30 sec) decrease (≥ 15 sec down, lasting ≥ 15 sec and < 2 min. from onset to return to BL)

Variable Decelerations

Variable Deceleration- Cause and Treatment Umbilical cord compression resulting in baroreceptor stimulation Treatment- Assess baseline variability, rate Reposition mother Notify provider Check for cord prolapse Apply internal monitors  or turn off oxytocin Administer O2 by mask Prepare for possible amnioinfusion Document interventions/FHR response

Late Deceleration Gradual decrease (≥ 30 sec) and gradual return to BL Delayed timing, nadir occurs after peak of U/C

Late deceleration

Late decelerations - Cause and Treatment Cause- Placental insufficiency Treatment Assess baseline variability, rate, accelerations Reposition mother on side  IV fluids  or turn off oxytocin Notify provider Administer O2 by mask Apply internal monitors Evaluate scalp stimulation Document interventions/FHR response Exit plan

Prolonged Deceleration Decrease in FHR below BL ≥ 15 sec, lasting ≥ 2 min. but < 10 min.

Causes of Prolonged Decelerations Uterine hyperstimulation or hypertonus Abruptio placenta Acute maternal hypotension Uterine rupture Maternal hypoxia Umbilical cord accidents Terminal fetal conditions Vasa previa Rapid fetal descent Vagal stimulation or maternal Valsalva

Treatment for Prolonged Decelerations Notify provider Assess baseline variability, rate, accelerations Reposition mother on side  IV fluids  or turn off oxytocin Administer O2 by mask Apply internal monitors Do not attempt scalp stimulation Document interventions/FHR response Exit plan

Sinusoidal FHR

Fetal Heart Rate Patterns Indeterminate FHR tracings that do not meet the criteria for Normal or Abnormal Abnormal Absent baseline variability and any of the following: Recurrent late decels Recurrent variable decels Bradycardia or Sinusodial pattern Normal ALL required: Moderate variability Baseline rate 110-160 No late or variable decels Early decels present or absent Accels: present or absent Category I Strongly associated with normal acid base status Category II Not predictive of abnormal fetal acid base status but inadequate evidence to classify as normal or abnormal Category III Predictive of abnormal fetal acid base status

Fetal Heart Rate Interpretation System Category l Associated with normal acid base balance Category ll Inadeq. evidence to classify as normal or abnormal Category lll Predictive of abnormal acid base status Normal Category l ALL of the following: normal BL, mod variability, accels present or absent, no late or variable decels, may have earlies Category ll ANY of the following: tachy, brady without abesnt variab. Min variabl. etc Requires continued surveillance and reevaluation Category lll EITHER sinusoidal pattern or absent variability w/ recurrent lates, recurrent variable decels or bradycardia Indeterminate Abnormal

FHR Interpretation Information about fetal oxygenation/placental function Somewhat subjective Abnormal patterns may need further testing

Monitoring Uterine Contractions Assess U/C pattern while assessing FHTs External Palpation EFM Toco measures frequency, duration Noninvasive Internal Intrauterine pressure catheter (IUPC) Measures exact intrauterine pressure Invasive

Why Monitor? FHR changes in response to oxygenation, gestation, and certain stimuli EFM provides more objective data than auscultation Infers information about current and ongoing fetal oxygenation EFM slightly more objective than Auscultation Shows fetal response to U/Cs Auscultation good for low risk; concerns? EFM helps to recognize patterns so need con’t record for interpretation

Interventions Abnormal FHR pattern: Notify provider Change maternal position Give oxygen via mask Increase IV fluids Consider medication to relax uterus

Other Fetal Surveillance Non-Stress Test (NST) - EFM Contraction Stress Test (CST) - EFM Biophysical Profile (BPP) - U/S Doppler Flow Studies/Growth - U/S Fetal Movement Count-maternal sensation/palpation

Intermittent Auscultation What’s the evidence? ACOG, AWHONN support the use of auscultation as an appropriate way to evaluate fetal heart rate for the uncomplicated patient Neonatal outcomes comparable to those with use of EFM based on randomized clinical trials

Technique for IA Assess contractions by palpation Determine fetal position Determine maternal pulse rate Place Doppler over fetal back or thorax Determine baseline FHR by listening between contractions for 30-60 seconds: differentiate from maternal HR Count FHR immediately after contraction for 30-60 seconds Chart under Intermittent Auscultation- Baseline, Rhythm, Increases, Decreases

How often? On admission, obtain 20 minute FM tracing If Category I tracing, no risk factors present, and provider order for IA: Document FHR and uterine activity: Latent phase: As ordered Active labor: Every 15-30 minutes Second stage: Every 5-15 minutes

Comparison Model for Palpation of Uterine Activity PALPATION OF UTERUS FEELS LIKE CONTRACTION INTENSITY • Easily indented • Tip of nose • Mild • Can slightly indent • Chin • Moderate • Cannot indent • Forehead • Strong

Limitations Difficult to hear FHR with if pt obese, has an increased AFI, or with maternal or fetal movement No tracing to review at a later time Certain EFM characteristics cannot be measured (sinusoidal pattern) Requires practice

Benefits Lower C/S and operative delivery rates compared to EFM for patients without risk factors Allows maternal freedom of movement/ambulation Increased hands-on contact with patient Increased patient satisfaction