E2: Fetal Assessment Flashcards
What is Antenatal Screening?
How does it differ from Prenatal diagnosis?
Antenatal screening is the process of identifying those at high risk of a disorder so they can be offered prenatal diagnosis. Prenatal diagnosis establishes whether or not the disorder is definitely present.
Thus, antenatal screening is step 1, while prenatal diagnosis is step 2.
What, in general, are the methods of fetal assessment discussed? (9)
- Uterine growth
- Fetal Movement Counting
- Non-Stress Test
- Contraction Stress Test
- Amniotic Fluid Assessment/Index
- Doppler Velocimetry
- Percutaneous Umbilical Blood Sampling
- BioPhysical Profile (BPP)
- Modified BPP
What is the general process behind Fetal Movement Counting?
What are the types of Fetal Movement Counting?
In Fetal Movement Counting, the fetus is monitored via transducer for 30 minutes to observe any of the described movements.
There are (3) Types of Fetal Movements that are counted;
- Gross Movement
- Fetal Tone
- Fetal Breathing Movements
Describe the type of fetal movements being observed in Gross Movement counting.
How are these movements scored?
In Gross Movement Counting, they are looking for discrete movement of the body or limb.
*These movements peak during week 32.
Score:
2/2: 3+ movements observed within 30m
0/2: <3 movements observed within 30m
Describe the type of fetal movements being observed in Fetal Tone counting.
How are these movements scored?
In Fetal Tone Counting, they are looking for both extension & flexion of an extremity (full cycle; i.e. opening & closing the hand).
Scoring:
2/2: 1 ext/flx cycle observed within 30m
0/2: Neither ext or flx observed within 30m
Describe the type of fetal movements being observed in Fetal Breathing Movements counting.
How are these movements scored?
While observing Fetal Breathing, they are looking for Rhythmic Paradoxical Chest movements associated with fetal respiration, lasting longer than 30s.
Scoring:
2/2: 1+ movements for 30s+ within 30m
0/2: No movements or duration is <30s
How is chest movement different in fetuses than in birthed humans during respiration?
When does fetal respiration primarily occur?
Chest movement is reversed in fetuses during respiration. That is, the chest wall collapses during inspiration and expands during expiration.
Fetal respiration primarily occurs;
- While Sleeping (0400-0700)
- Following breakfast (1000-1700)
Minimum from 2000-2400
Which method of assessment can be used at the earliest point in gestation?
Fetal Movement Counting @ 20W
Which Method of Assessment requires the longest waiting period to be used?
Contraction Stress Test @ 36W
Give the General Trend of initiation time for the Methods of Assessment from earliest to latest.
Earliest:
- Fetal Movement Counting @ 20W
- Doppler Velocimetery/Ultrasound @ 24W
- Fetal BPP @ 28W
- Modified BPP / NST @ 32W
- Constraction Stress Test @ 36W
Latest:
Describe the process of the Non-Stress Test and what is being tested/monitored.
How does the duration change if there is some variability in one of the aspects being monitored?
- Patient (mother) lies in a lateral tilt position
- External transducer monitors the Fetal HR & Uterine Activity for 20 minutes
- Simultaneously, the mother records movements by clicking a button, which is recorded on the record.
If there is variability found in the FHR, the duration can be extended up to 40 minutes.
Describe the process of the Contraction Stress Test and what is being tested/monitored.
Contraction Stress tests consists of;
- NST
- Uterine Contraction Test
Uterine Contraction Test procedures;
- Uterine Conctractions are induced via Oxytocin administration
- Alter dosage to achieve 3+ contractions lasting 40s+ over 10m
- These conditions MUST be met for the test to be interpreted
- Interpretation & Analysis
What are the potential results from the Uterine Contraction Test?
Negative: No late or significant Variable Decelerations
Positive: Late Decelerations following 50% or more of the contractions
Equivocal-Suspicious: Intermittent late decelerations or significant variable decelerations
Equivocal-Hyperstimulatory: FHR Decelerations occur in the presence of contractions more frequent than every 2m or exceeding 90s
Unsatisfactory: Fewer than 3 contactions in 10m or uninterpretable
Describe the process of the Amniotic Fluid Index.
In the AFI, the depth of the largest vertical pocket (free of fetal parts/cord) is measured.
Scoring:
2/2: 2cm+
0/2: <2cm
What is the fetal BioPhysical Profile?
What do the findings of this profile aim to identify?
The BPP consists of (5) Variables;
- (3) Fetal Movement variables visualized by US in real time
- Gross, Tone, & Breathing
- NST
- Amniotic Fluid Vol.
The aim of this profile is to reflect that the fetus can accelerate it’s HR, move appropriately, and is surrounded by adequate amniotic fluid. These suggest that the fetus is not hypoxic.
Taking into account the (5) variables in the BPP, what does a score of 10 indicate?
10/10: Normal, Nonasphyxiated fetus
No fetal indication for intervention
Taking into account the (5) variables in the BPP, what does a score of 8/10 indicate?
There are (2) interpretations of 8/10, which differ based on the Amniotic Fluid Vol (AFV).
8/10 w/ Normal AFV: Normal, nonasphyxiated Fetus
8/10 w/ Decreased AFV: Chronic Fetal Asphyxia suspected
Deliver the baby
Taking into account the (5) variables in the BPP, what does a score of 0-2/10 indicate?
0-2/10: Almost certain fetal asphyxia
Emergency Delivery.
What is the Modified BPP?
The modified BPP consists of only (2) tests;
- NST
- AFI
What are the possible results of the Modified BPP?
Normal: Reactive NST & AFI range of 5-25cm
Abnormal: Non-Reactive NST AND/OR AFI range is <5cm
Describe Umbilical Artery Doppler Velocimetry.
In what type of cases is it commonly used in?
Doppler UltraSonography is a (noninvasive) technique used to assess the hemodynamic components of vascular impedance.
It is often used in cases of Fetal Growth Restriction (FGR)
What is being assessed in Umbilical Blood Sampling?
The UBS is used to assess the pH of the blood within the umbilical cord.
What is the mean umbilical arterial & venous pH?
Arterial: 7.27
Venous: 7.34
Give the associated Antepartum umbilical venous pH for each fetal BPP score
8-10: 7.37 ish
6: 7.33 ish
4: 7.28 ish
2: 7.20
0: 7.07 ish
What are the components of the APGAR Scoring System?
A: Activity (Muscle tone)
P: Pulse
G: Grimace (reflex irritability)
A: Appearance (skin color)
R: Respiration
Describe the Scoring system for the Activity Component of the APGAR.
Activity (Muscle Tone):
0: Absent
1: Flexed arms & Legs
2: Active
Describe the Scoring system for the Pulse Component of the APGAR.
Pulse:
0: Absent
1: <100bpm
2: >100bpm
Describe the Scoring system for the Grimace Component of the APGAR.
Grimace (relfex irritability):
0: Floppy
1: Minimal response
2: Prompt response
Describe the Scoring system for the Appearance Component of the APGAR.
Appearance of skin color:
0: Pale blue
1: Pink body; blue extremities
2: Whole body is pink
Describe the Scoring system for the Respiration Component of the APGAR.
Respiration:
0: Absent
1: Slow & Irregular
2: Vigorous Cry
In the assessment of Fetal HR, describe category I
Category I: Normal fetal acid-base status: Well-oxygenated Fetus
- Baseline rate: 110-160bpm
- Baseline Variability: Moderate
- Late/variable Decels: Absent
- Early Decels: Present or absent
- Accels: present or absent
In the assessment of Fetal HR, describe category II
Category II: Indeterminate: Compensatory Response
Examples;
- Late/variable Decels: Moderate
- Recurrent variable Decels: Minimal
- Variability w/o recurrent decels: Absent
- Prolonged Decels
- Bradycardia w/ moderate variability
- Tachycardia
In the assessment of Fetal HR, describe category III
Category III: Abnormal fetal Acid-Base Status
Either;
- Absent variability with;
- Recurrent late decels
- Recurrent variable decels
- Bradycardia
- Sinusoidal pattern
How is the Baseline FHR deterimined?
What is considered a “Normal” Baseline?
Baseline FHR is the mean FHR rounded to 5bpm within a 10m period.
*Accels, Decels, and marked variability is excluded when assessing the Baseline
Normal Baseline FHR is a mean FHR of 110-160bpm over 10m.
How is Bradycardia & Tachycardia defined?
Abnormal Baseline FHR:
Bradycardia: FHR <110bpm over 10m
Tachycardia: FHR >160bpm over 10m
What is an early & late decel?
An Early Decel is a decrease and return of the FHR to baseline associated with a uterine contraction.
- Symmetric & gradual
- Onset to Nadir is 30s+
- Onset mirrors onset of contaction
- Nadir mirrors peak of contraction
- Recovery mirros end of contraction
Late decel mirrors the above.
What is a mild or Severe variable Decel?
Mild Variable Decel:
FHR Decrease <60bpm below baseline for <60s
Nadir > 60bpm
Severe Variable Decel:
FHR Decrease >60bpm below baseline for >60s
Nadir <60bpm
What is a prolonged deceleration?
FHR decrease <15bpm below baseline for 2-10m
What is a baseline change?
Baseline change is a FHR decrease lasting >10m
What are recurrent & intermittent decels?
Recurrent:
If any FHR decrease occurs >50% of uterine contractions within 20m period
Intermittent:
If any FHR decrease occurs <50% of uterine contractions within 20m period
What is considered and Accel?
FHR increase of 15bpm above baseline for 15s concurrent w/ fetal movement.
What are the significant components of the US exam in the 1st Trimester
- Crown-Rump length
- Embryonic/Fetal Cardiac Activity
What are the significant components of the US exam in the 2nd & 3rd Trimester
- Fetal Cardiac Activity
- AFV
- Gestational Age assess
- Fetal Weight estimation
- Fetal Anatomical Survey
What is the purpose of the M-mode US?
The M-mode examines a line of motion over time, which displays the movement of the myocardium, and thus demonstrates embryonic cardiac activity.
