Fetal Monitoring Basics

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

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 ContinuousExternalUltrasound transducerTocotransducerInternalFetal Scalp ElectrodeIntrauterine Pressure Catheter

Fetal Monitoring Setup

Fetal Heart Rate CharacteristicsEvaluate to determine fetal statusNICHD terminologyBaseline 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 at least 2 min. period during 10 minute segmentTachycardia - >160 bpm for >10 minutesBradycardia - 10 minutesBaseline

Classifications of FHR VariabilityFluctuations in FHR, irregular in frequency and amplitudeAbsent 0-2 bpmMinimal >2 25 bpm

Absent Variabilty

Minimal Variability

Moderate Variability

Marked Variability

Periodic/Episodic Changes

Periodic with uterine contractionsEpisodic without uterine contractions

AccelerationsAbrupt increase in FHR above BLPresent or Absent< 32 wks gestation Peak 10 bpm above BL for at least 10 sec.>32 wks gestationPeak 15 bpm above BL for at least 15 sec.

Accel 10 min. is defined as BL changeAccelerationsAbrupt increase in FHR above BLPeak 15 bpm above BL for at least 15 sec.

Increase in FHR with fetal activity, just like adult HR increases with exerciseAt times, fetus moves in response to U/Cs A sign of fetal well-being

16Recognition Criteria for Fetal Heart Rate AccelerationsTransient 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 DecelerationsEarly Gradual decrease and return to BL, mirrors the U/CVariable Abrupt (