Uteroplacental & Fetal Physiology Pt. 5 (Exam 2) Flashcards
(46 cards)
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
