Fetal Heart (Moulton) Flashcards
Benefit of Fetal Rate Heart (FHR) Monitoring
reassurance that >98% that good fetal/neonatal outcome is associated with normal continuous FHR data
Which fetal monitoring provides the most accurate tracing?
internal monitoring; Fetal scalp electrode - avoid in HIV pts and Intrauterine pressure catheter (IUPC)
Pressure sensitive tocodynanmometer transducer
external fetal monitoring; detects and records contractions; DOES NOT provide strength of the contraction
Fetal oxygen reserve
only enough to meet metabolic demands for approx. 1-2 mins
How is the fetal heart rate determined?
by atrial pacemakker
Normal pH of fetal scalp blood
pH 7.25-7.30
**acidosis pH <7.20
Fetal scalp pH of what is considered abnormal/acidotic?
pH <7.20; normal range pH 7.25-7.30
Normal uterine contractions
5 contractions or less in 10 mins or 3 contractions in 8 mins (once every 2-3 mins)
Tachysystole >5 contractions in 10 mins
When are uterine contractions considered tachysystole?
> 5 contractions in 10 mins
Normal fetal heart rate
normal 110 - 160 bpm
tachycardia >160 bpm
bradycardia <110 bpm
What is the most common cause of fetal tachycardia?
Fetal infection - chorioamnionitis
What is the normal fetal heart rate variability?
amplitude range 6-25 bpm
minimal <5 bpm
marked >25 bpm
absent = undetectable
Decreased fetal heart rate variability
indicator for fetal stress; associated with hypoxia and acidemia; can be caused by: maternal drugs/substance abuse, maternal hyperthyroidism, prematurity
Accelerations
fetal heart rate changes with uterine contractions; an increase in FHR is a normal reassuring response >32 weeks; FHR above 15 bpm for about 2 mins
Prolonged accelerations
FHR above 15 bpm for more than 2 mins; not too concerning
Decelerations
FHR decreases in response to uterine contractions; classified as early, variable and late
Early decelerations
deceleration occurs at the same time as the peak of the contraction and thus “mirror image”; not associated with fetal distress
Variable decelerations
secondary to umbilical cord compression; big “V” for variable; can occur before, during, or after contractions start
Late decelerations
deceleration occurs after peak of contraction; caused by uterine placental insufficiency (UPI); most ominous deceleration (very concerning); usually indicated fetal metabolic acidosis or low arterial pH
What is the most ominous deceleration?
a late deceleration; usually indicated by fetal metabolic acidosis or low arterial pH
Potential causes of late decelerations
Excessive uterine activity
Maternal supine hypotension
The pattern on Fetal Heart Monitoring indicating fetal anemia
Sinusoidal pattern; smooth wave-like undulating pattern
What is the best fetal heart category to be in?
category I - normal
Which fetal heart category do you start getting nervous about?
category III - abnormal; sinusoidal pattern; absent baseline variability
When the fetal scalp is stimulated, fetal pH should almost always be greater than what?
pH 7.22 or greater
Electronic Fetal monitoring has a >99% false positive rate for detecting what?
cerebral palsy
