Uteroplacental & Fetal Physiology Pt. 5 (Exam 2) Flashcards
What is a fetal heart rate deceleration? What are the three types of FHR decelerations?
Temporary drop in FHR
- Early
- Late
- Variable
Each of these can also be “prolonged” and/or “severe”
What occurs with FHR as a contraction increases in intensity?
↑ contraction = ↓ FHR
What are early decelerations?
gradual decrease in FHR with return to baseline associated with uterine contraction: benign
- decel onset to nadir of FHR > 30seconds
What is the physiologic cause of benign early decelerations?
Vasovagal response to fetal head compression (↓CBF) from uterine contraction.
Early decelerations are more typical during the _____ stage of labor.
active
What type of deceleration is depicted below?
Variable decelerations
- ttypically jagged & irregular
- U, V or W shaped
An abrupt decrease in FHR and an abrupt return to baseline is indicative of _________ decelerations.
variable
The onset of variable decelerations to the beginning of FHR nadir is typically _____ seconds.
< 30 seconds
What is the most common cause of variable decelerations?
Transient Hypoxemia
- Temporary cord compression (happens during most labors).
- 2ⁿᵈ stage of labor (fetal head compression)
- Oligohydramnios (low amniotic fluid)
Frequent variable decelerations or variable decelerations occurring early in labor are often an indicator for what?
Umbilical cord occlusion
Indicative for operative delivery.
What is oligohydramnios?
Low volumes of amniotic fluid
What characterizes severe decelerations?
- FHR < 70 bpm
- ↓ in FHR > 60bpm from baseline
Severe decelerations + minimal/absent FHR variability should be concerning for what?
Fetal Hypoxia
Late decelerations can be benign as long as _______ is present.
FHR variability
What type of decelerations are depicted below?
Late decelerations
What type of decelerations are depicted below?
Late decelerations
What are some non-benign causes of late decelerations?
- Hypoxemia
- Myocardial decompensation/failure
- Chorioamnioitis
- Post-term gestation
- Uterine hyperactivity
- Maternal HoTN/HTN
- Smoking
- Anemia
- Placental abruption/previa
poor maternal health
How would hypoxemia present alongside late decelerations?
Late decels + fetal tachycardia w/ minimal/absent variability
Late decelerations w/ _______ FHR variability is very bad.
absent/decreased
What type of decelerations are characterized by decrease in FHR ≥ 15bpm and lasting > 2 minutes (but less than 10 min)?
Prolonged decelerations
if decel lasts >10min = baseline change
What are some of the causes of prolonged decelerations?
- Umbilical cord compression
- Prolonged maternal HoTN/hypoxia
- Tetanic uterine contractions
- Prolonged head compression in 2ⁿᵈ stage of labor
What type of decelerations are indicated below?
Prolonged decelerations
What type of deceleration is depicted below?
Severe decelerations
What type of FHR tracing is exhibited below?
Sinusoidal pattern
What does persistent sinusoidal FHR tracings indicate?
requires Obstetric intervention
What are common causes of sinusoidal pattern FHR tracings?
- Fetal anemia
- Rh disease (incompatible blood)
- Severe hypoxia
Which category of FHR tracings is predictive of normal fetal acid-base status?
Category I
What are characteristics of Category I FHR tracings?
- Baseline FHR 110 - 160 bpm
- Moderate variability
- No late/variable decels
- +/- early decels
- +/- accelerations
What are the characteristics of Category II of FHR tracings?
- Fetal tachycardia
- Absence of induced accelerations w/ fetal stimulation
- Prolonged decels > 2min but < 10min
- Recurrent late decels w/ moderate variability
Are Category II FHR tracings predictive for abnormal fetal acid-base status?
No, they are not predictive of abnormal fetal acid-base status
What are the characteristics of Category III of FHR tracings?
- Sinusoidal FHR pattern
- Absent FHR variability w/ recurrent late decels
- Recurrent variable decels
- Sustained fetal bradycardia
Which category of FHR tracings is predictive for abnormal fetal acid-base status?
Category III
What are some things that can be done to address Category III FHR tracings?
- Maternal position change
- Discontinue pitocin (labor augmentation)
- Treat tachysystole
- Surgical delivery
What are the five components of the Apgar scoring system?
- HR
- Respiratory effort
- Muscle tone
- Reflex irritability
- Color
A: activity
P: pulse
G: grimace
A: appearance
R: respirations
Each score ranges from 0-2 (0 is poor, 2 is best)
An apgar score range of _____ is considered normal.
8 - 10
An apgar score range of ______ is considered moderate impairment.
4 - 7
An apgar score range of ______ requires immediate neonate resuscitation.
0 - 3
Risk for neonate mortality is __________ proportional to the apgar 1 minute score.
inversely
Lower score = higher risk of mortality
What measurement parameters typically correlate with variable decelerations?
- FHR decreases 15 bpm or more
- lasts 15 seconds or longer
- < 2min duration
Why does fetal head compression cause bradycardia?
dural stimulation ⇒ increased vagal discharge
Contraction duration > 60 seconds can lead to what kind of deceleration? why?
severe decelerations
- decreased umbilical blood flow
- impaired fetal cardiac output
What is characteristic of late decelerations?
- symmetric gradual decrease in FHR with return to baseline
- begin after peak of contraction, or after contraction is over
Review: this is a depiction of a prolonged deceleration
prolonged deceleration
What are characteristics of sinusoidal FHR patterns?
- smooth, wave-like, undulating (smooth rise/fall)
- frequency of 3-5 cycles per minute
- amplitude range 5-15bpm
- persists > 20 min
How is the apgar scoring system typically assessed?
- assessed at 1 minute & 5 minutes
- score of 0-2 per parameter
Review the APGAR scoring parameters
