FHR Monitoring Basics Flashcards
Normal uterine contraction
Tachysystole
Normal: 5 contractions or less in 10 min. averaged over 30 min.
Tachysystole: > 5 contractions in 10 min. (may have FHR)
Normal FHR
Tachycardia
Bradycardia
NL: 160>HR>110
Tachycardia: X>160
Bradycardia: X<110
What are possible causes of fetal tachycardia? (6)
Hypoxia (early) Arrhythmias Some meds Prematurity Maternal fever Choramnionitis
What are possible causes of fetal bradycardia? (5)
Hypoxia (late) Anesthesia Pitocin Maternal hypotension Heart block
Absent variability
Minimal variability
Moderate (NL) variability
Marked variability
Absent variability: undetectable
Minimal variability: /< 5 bpm
Moderate (NL) variability: 6-25 bpm
Marked variability: > 25 bpm
What can cause decreased variability?
In which case is it very concerning?
Fetal stress
If associated with late decelerations: hypoxia and acidosis
What is normal accelerations if:
> / 32 wks
<32 wks
At what point are accelerations considered “prolonged”?
> / 32 wks: HR >/ 15 bpm for 15 sec
< 32 wks: HR >/ 10 bpm for 10 sec
If lasting > 2 min
What causes accelerations? (3)
Spontaneous fetal movements
Scalp is touched
Vaginal exam
What causes early decelerations?
Fetal distress?
What is the relationship of the the nadir and the deceleration?
Secondary to head compression; it is a fetal ANS response to increased intracranial pressure.
No fetal distress
They occur simultaneously
What causes variable decelerations?
What are the requirements?
What is the relationship of the the nadir and the deceleration?
Secondary to umbilical cord compression, leading to rapid decrease in FHR.
FHR >/ 15 bpm lasting >/ 15 sec and less than 2 min
Variable
What causes late decelerations?
Why is it most ominous?
What is the relationship of the the nadir and the deceleration?
Uterine placental insufficiency (UPI)
It is associated with metabolic acidosis and low arterial pH
Nadir occurs after the peak of contraction.
