Lecture Six: Methods of Assessing Fetal Status

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Lecture Six Methods of Assessing Fetal Status

• NURS 2208
• T. Dennis RNC, MSN

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Objectives

• Identify antenatal surveillance indicators
• Discuss the use of ultrasound in pregnancy
• Discuss methods of antenatal fetal surveillance
• Compare NST, CST and BPP
• Contrast amniocentesis and CVS
• Discuss Leopolds maneuver
• Compare various fetal heart rate patterns and
  interventions

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Indications for Antenatal Surveillance (pg. 439)

• Decreased fetal movement
• Elevated maternal serum AFP
• Hemoglobinopathies
• Fetal heart rate arrythmias
• Infections
• Maternal disease
• PIH Pregnancy Induced Hypertension

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Fetal Monitoring

• Fetal oxygen supply must be maintained during
  labor to prevent fetal compromise and promote
  newborn health after birth.
• Reduction of blood flow through the maternal
  vessels.
• Reduction of the oxygen content in the maternal
  blood.
• Alteration in fetal circulation.
• Reduction in blood flow to the intervillous space
  in the placenta secondary to uterine hypertonus.

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Monitoring Techniques

• Intermittent Auscultation
• Electronic Fetal Monitoring
• Fetal blood sampling
• FHR response to stimulation
• Fetal oxygen saturation monitoring
• Cord blood sampling

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Determination of Fetal position and Presentation
(pg. 515)

• Inspection
• Palpation Leopolds Maneuvers 1) Find the
  head/buttocks, 2) Find the back, 3) Determine
  presenting part, 4) Determine brow
• Vaginal examination
• Ultrasound

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Intermittent Auscultation

• Listening to fetal heart sounds at periodic
  intervals to assess the FHR.
• Fetoscope or doppler
• Perform Leopolds to determine fetal back
• Palpate maternal pulse
• Count between contractions for baseline and 30
  seconds after the contraction
• 1 hr, 30 minutes, 15 minutes or 30 minutes, 15
  minutes and 5 minutes.

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Electronic Fetal Monitoring

• External method involves the use of external
  transducers placed on the maternal abdomen to
  assess uterine contractions and the FHR.
• Internal method uses spiral electrode and
  intrauterine pressure catheter to monitor and
  record FHR, uterine activity and intrauterine
  pressure.

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External Fetal Monitoring

• FHR Ultrasound transducer
• High frequency sound waves
• used antepartally and intrapartally
• noninvasive
• Does not require RBOW or dilatation

• Uterine activity Tocotransducer
• Monitors frequency and duration of contractions
  by use of a pressure sensing device on abdomen
• Antepartally and intrapartally
• Noninvasive

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External Fetal Monitoring
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Internal Fetal Monitoring

• FHR Spiral electrode
• converts fetal ECG to via cardiotachometer
• Used when RBOW
• Cervix dilated
• Penetrates presenting part
• Must be securely attached

• Contractions IUPC
• measures frequency, duration and intensity of
  contractions
• two types
• measure intrauterine pressure at catheter tip
• Used with RBOW and dilatation

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Internal Fetal Monitoring
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Baseline Fetal Heart Rate

• Baseline fetal heart rate
• Tachycardia
• Bradycardia
• Variability

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Baseline Fetal Heart Rate

• The average rate during a ten minute segment that
  excludes periodic and non-periodic (episodic)
  changes, periods of marked variability, and
  segments that vary by more than 25 BPM.
• Normal range is 110-160.

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Tachycardia

• A baseline FHR above 160 BPM for a ten minute
  period or greater.
• Can be considered an early sign of fetal hypoxia.
• Can result from maternal or fetal infection,
  maternal hyperthyroidism, or fetal anemia.
• May occur in response to drugs such as
  terbutaline, atropine, cocaine.

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Bradycardia

• A baseline FHR below 110 BPM for a period greater
  than 10 minutes.
• Considered a later sign of fetal hypoxia.
• Known to occur before fetal demise.
• Can occur from drugs (anesthetics, prolonged
  compression of the umbilical cord, maternal
  hypotension or hypothermia.

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Variability

• Described as irregular fluctuations in the
  baseline FHR of 2 cycles per minute or greater.
• Described as short term or long term.
• Absent or undetected variability
• Minimal variability (lt 5 BPM)
• Moderate variability (6 to 25 BPM)
• Marked variability (gt 25 BPM)

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Variability

• In clinical practice used to describe
  fluctuations in the FHR.
• Absence of variability is considered
  non-reassuring.
• May result from fetal hypoxemia and acidosis (may
  be related to drugs).
• A temporary decrease can occur with fetal sleep.

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Periodic and Non-periodic FHR Changes

• Accelerations
• Decelerations
• Early deceleration
• Late deceleration
• Variable deceleration
• Prolonged deceleration

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Accelerations

• A visually apparent abrupt increase in FHR above
  the baseline rate.
• Increase is 15 BPM or greater that lasts 15
  seconds or more with return to baseline in less
  than 2 minutes.
• Can be periodic or non-periodic (episodic).
• Indications of fetal well being.

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Decelerations

• May be benign or non-reassuring.
• Described by their relation to the onset and end
  of the contraction and shape.
• Three types
• Early decelerations
• Late decelerations
• Variable decelerations
• Prolonged Decelerations

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Early Decelerations

• Gradual decrease in and return to FHR baseline.
• In response to head compression.
• Uniform in shape.
• Seen with pushing.
• No intervention required.

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Late Decelerations

• Caused by uteroplacental insufficiency
• Begins after beginning of ctx and ends after end
  of the contraction.
• May be correctable or ominous

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Variable Decelerations

• Caused by umbilical cord compression
• Abrupt in descent and return to baseline
• May occur early or late in labor
• May be repetative

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Prolonged Decelerations

• May be caused by vaginal exam, spiral electrode
  application, etc.
• Usually isolated events
• May occur just before fetal death.

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Fetal Well-being

• Can be measured by response of the FHR to uterine
  contractions.
• FHR patterns can be described as reassuring or
  non-reassuring.

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Reassuring FHR patterns

• Baseline FHR in the normal range of 110 to 160
  BPM with no periodic changes and a moderate
  baseline variability.
• Accelerations with fetal movement.

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Non-reassuring Patterns

• Progressive increase or decrease in the fetal
  baseline
• Tachycardia of 160 BPM or more
• Progressive decrease in baseline variability
• Severe variable decelerations

• Late decelerations of any magnitude
• Absence of FHR variability
• Prolonged deceleration
• Severe bradycardia

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Normal Uterine Activity

• Occurring every 2 - 5 minutes
• Lasting less than 90 seconds
• Moderate to strong in intensity (by palpation or
  100mm Hg by IUPC)
• 30 second lapse period between contractions
• Uterine relaxation between ctx by palpation or 15
  mm Hg by IUPC

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Fetal Compromise

• The goals of intrapartum FHR monitoring are to
  identify and differentiate the rassuring from the
  nonreassuring , which can be indicative of fetal
  compromise.
• Nonreassuring FHR patterns are those associated
  with fetal hypoxia (a deficiency in oxygen in the
  arterial blood) and if uncorrected hypoxia (at
  the cellular level).

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Nonstress Test NST (pg. 452-454)

• A reactive NST shows two or more accelerations
  of 15 bpm or more within 20 minutes of beginning
  the test.
• A nonreactive NST contains a tracing that does
  not meet the above criteria. Accelerations are lt
  two in number or lt 15 bpm or no accelerations are
  present.

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Contraction Stress Test CST(pg. 455)

• Contractions occurring spontaneously
• Nipple stimulation
• Necessary component is the presence of three
  uterine contractions of at least 40 sec duration
  in 10 minute span
• Not done prior to prior to 28 wks gestation
• NEGATIVE, POSITIVE EQUIVOCAL

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Biophysical Profile (BPP)

• Assessment of 5 variables in the fetus that help
  to evaluate fetal risk breathing movement, body
  movement, tone amniotic fluid volume, and fetal
  heart rate activity.
• A score of 8 to 10 is normal.
• A score of 6 or below indicates fetal compromise

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Fetal Acoustic Stimulation Test

• Lets buzz the baby!!!!!

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Ultrasound

• Most common diagnostic procedure
• 70 of pregnant women have at least one
• Abdominal, vaginal, or labial
• May be basic or limited
• Can evaluate both structural and functional
  characteristics
• BP diameter, head circumference, femur length,
  abdominal measurements
• Fetal growth, congenital anomalies, placental
  growth and location, cervical length

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Amniocentesis (pg. 457-459)

• A simple procedure needle is inserted through
  the maternal abdomen into the uterine cavity to
  withdraw a sample of amniotic fluid.
• Early pregnancy DNA studies
• Late Pregnancy Lung maturity
• Complications Preterm labor, fetal scratches,
  maternal hemorrhage, infection, Rh sensitization
  (RhoGam may be indicated)

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Tocolytic Therapy

• Tocolysis can be achieved by administering drugs
  that inhibit uterine contractions.
• May be used during management of fetal
  compromise.
• Magnesium sulfate, terbutaline, nifedipine may be
  used.

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Maternal Positioning

• Maternal supine hypotensive syndrome is caused by
  the weight and pressure of the gravid uterus on
  the ascending vena cava when the woman is in a
  supine position.
• A side-lying position or semi-fowlers position
  with a lateral tilt to the uterus is recommended.

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Other Available Tests(pg. 459-467)

• AFP (Amniotic Fluid)
• Rh sensitized pregnancies
• Fetal Maturity
• L/S ratio and PG
• CVS
• Fetoscopy
• Percutaneous Umbilical Blood Sampling
• MRI

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EFM Nursing Diagnosis

• Maternal anxiety related to lack of knowledge
  about use of electronic fetal monitor.
• Risk for fetal injury related to inaccurate
  placement of transducers/electrodes,
  misinterpretation of results or failure to use
  other assessment techniques to monitor fetal
  well-being.

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Nursing Assessment Diagnosis

• Knowledge Deficit related to insufficient
  information about the fetal assessment test and
  its purpose, benefits, risks, and alternatives
• Fear related to the specific test or possible
  unfavorable results
• Disruption in bonding due to high risk label

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Questions?