Basic Fetal Monitoring
Normal Assessment Findings - ANS-• FHR between 110-160 in gestations 32-40+
weeks
• Rates slightly above 160 are normal in gestations less than 32 weeks.
• Regular rhythm
• Increases in the FHR associated with fetal movement that return to original rate range
Methods of Electronic Fetal Monitoring External - ANS-Noninvasive method
Utilizes an ultrasonic transducer to monitor the fetal heart Utilizes the tocodynamometer
(toco) to monitor uterine contraction pattern
external fetal monitor setup with ultrasound transducers to monitor fetal heart rate
patterns
Contractions are determined by a ____________ attached by a belt to the woman's
abdomen at the level of the fundus. Is accurate in determining frequency & duration of
contractions, but may not be accurate in determining the strength of the contractions. -
ANS-tocodynamometer
Internal Fetal Monitoring - ANS-Invasive
FHR is monitored via a fetal scalp electrode
Uterine activity is monitored by an intrauterine pressure catheter (IUPC)
A combination of external and internal fetal monitoring is common practice
Advantages of Internal Fetal Monitoring - ANS-Patient can move without much
interference in data transmission
More accurate measurement of data
Data less likely to be affected by artifact
Disadvantages of Internal Fetal Monitoring - ANS-Invasive
Membranes have to be ruptured and cervix dilated
Application requires more skill
Procedure is uncomfortable for the mother
Risk of trauma and infection for mother and fetus
Components of the Fetal Monitor Paper Tracing - ANS-Strip has two components
Upper graph - records FHR data
Small squares represent 10 bpm increases as well as 10 seconds duration
, Lower graph records contraction data
Small squares represent 10 second duration or 10 mmHg intensity
Dark line to dark line represents one minute of time
Baseline FHR - ANS-Normal baseline FHR in a term fetus 37 completed weeks or more
is 110-160 bpm.
Determination of the baseline FHR is done between contractions
Baseline is rounded in increments of 5 bpm example; if the FHR is running 125-135
then the baseline FHR should be documented as 130
FHR Variability - ANS-Normal changes and fluctuations in the FHR over time.
Best assessed between contractions
Considered to be the best indicator of fetal well-being
Variability can be influenced by hypoxic events, maternal hemodynamic issues, drugs,
etc.
Examples of Variability - ANS-Absent: Not detectable from baseline
Minimal: Less than 5 bpm from baseline
May occur with:
• normal fetal sleep patterns
• mother has received analgesia for pain
Moderate : 6-25 bpm from baseline (optimal pattern)
Marked: More than 25 bpm from baseline
How Do Uterine Contractions Affect Fetal Heart Rate? - ANS-Can affect FHR by
increasing or decreasing the rate in association with any given contraction.
3 primary mechanisms by which Uterine Contractions can cause a decrease in FHR -
ANS-Fetal head
Umbilical cord
Uterine myometrial vessels
Periodic FHR - ANS-Refers to changes in the FHR that occur with or in relationship to
contractions
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