Fetal Monitoring Basics NUR 134 M. Johnston, RN-BC, M.Ed.
Dec 23, 2015
Types of MonitoringAuscultation- listen to fetal heart rate (FHR)
Electronic Fetal Monitoring – use of instruments to record FHR and uterine contractions(U/Cs)
AuscultationDoppler - ultrasound converts sounds waves to signals of
fetal heartFetoscope - Like stethoscope, open end pressed on
abdomen, used less frequently
Electronic Fetal MonitoringMeasures response of FHR to uterine contractions (U/Cs)Intermittent or ContinuousExternal
Ultrasound transducerTocotransducer
InternalFetal Scalp ElectrodeIntrauterine Pressure Catheter
Fetal Monitoring Setup
http://www.youtube.com/watch?v=DvcDXvlCXAE&feature=player_embedded
Fetal Heart Rate CharacteristicsEvaluate to determine fetal statusNICHD terminology
Baseline RateBaseline VariabilityAccelerations (present or absent)Decelerations (present or absent)Changes or trends over time
Baseline (BL)Normal range 110-160 bpmMeasure between U/Cs for 10 min. periodTachycardia - >160 bpm for >10 minutesBradycardia - <110 bpm for >10 minutes
Classifications of FHR VariabilityFluctuations in FHR, irregular in frequency and amplitude
Absent 0-2 bpmMinimal >2 <6 bpmModerate 6 -25 bpmMarked >25 bpm
AccelerationsAbrupt increase in FHR above BLPresent 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
Types of DecelerationsEarly – Gradual decrease and return to BL, mirrors the
U/CVariable – 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/CProlonged – Decrease in FHR below BL ≥15 sec, lasting ≥
2 min. but <10 min.
Variable DecelerationAbrupt (<30 sec) decrease (≥ 15 sec down, lasting ≥
15 sec and < 2 min. from onset to return to BL)
Late DecelerationGradual decrease (≥ 30 sec) and gradual return to BLDelayed timing, nadir occurs after peak of U/C
Fetal Heart Rate Interpretation System
Category lAssociated with normal acid base
balance
Category lllPredictive of abnormal acid base
status
Normal
Indeterminate
Abnormal
FHR InterpretationInformation about fetal oxygenation/placental functionSomewhat subjectiveAbnormal patterns may need further testing
Monitoring Uterine ContractionsAssess U/C pattern while assessing FHTs
ExternalPalpationEFM Toco measures frequency, durationNoninvasive
InternalIntrauterine pressure catheter (IUPC)Measures exact intrauterine pressure Invasive
Why Monitor?FHR changes in response to oxygenation, gestation, and
certain stimuliEFM provides more objective data than auscultationInfers information about current and ongoing fetal
oxygenation
InterventionsAbnormal FHR pattern:
Change maternal positionGive oxygen via maskIncrease IV fluidsConsider medication to relax uterus