QUESTION SET AND SOLUTIONS
◉ what are some causes of sinusoidal rhythm?
Answer: - severe fetal anemia
- congenital cardiac anomalies
- erythroblastosis fetalis from fetal-maternal Rh incompatibility
- fetal-maternal hemorrhage
- fetal hemorrhage
- fetal infection
- twin-to-twin transfusion syndrome
- congenital hydrocephalus
- gastroschisis
- can be transient after administration of maternal IV opioids
◉ what is definitions of variability in EFM?
Answer: fluctuations in baseline FHR (more than 2 cycles per
minute) that are irregular in amplitude and frequency; variability is
measured from peak to rough of FHR fluctuations and is visually
quantified in BPM
◉ what does variability determine?
,Answer: fetal oxygen reserve
◉ FHR variability can be interpreted with an external monitor using
doppler technology called...
Answer: autocorrelation
◉ what is absent variability?
Answer: amplitude range is visually undetectable
◉ what is minimal variability?
Answer: visually detectable from baseline but less than 5 bpm
◉ what is moderate variability?
Answer: amplitude range 6 to 25 bpm
◉ moderate variability is a key indicator of...
Answer: intact fetal cerebral oxygenation
indicates normal neurologic regulation of FHR at time of
observations, but does not exclude possibility of preexisting
neurologic injury
◉ moderate variability reliably predicts...
, Answer: the absence of fetal metabolic acidemia and ongoing
hypoxic injury at the time it is observed
an observation of minimal or absent variability alone does not
reliably predict the presence of fetal hypoxemia or metabolic
acidemia
◉ what is marked variability?
Answer: greater than 25 bpm
significance is unknown
◉ marked variability mostly seen with...
Answer: fetal movement or stimulation
◉ no distinction is made between short-term variability and long-
term variability because...
Answer: in actual practice, they are visually determined as a unit
◉ what are some potential causes of decreased fetal heart rate
variability?
Answer: - fetal sleep cycle
- fetal tachycardia
- medications
- prematurity