EFM - Electronic Fetal Monitoring Periodic and Episodic Changes Questions and Answers — Questions and Answers
Question 1: A fetal heart rate tracing shows recurrent decelerations where the onset, nadir, and recovery are delayed relative to the beginning, peak, and end of the uterine contractions. This pattern is most indicative of which underlying condition?
- Umbilical cord compression
- Fetal head compression
- Uteroplacental insufficiency (Correct answer)
- Maternal supine position
Correct answer: Uteroplacental insufficiency
Late decelerations are characterized by a gradual decrease in the FHR with the nadir occurring after the peak of the contraction. This timing reflects a delayed fetal response to transient hypoxemia caused by reduced blood flow to the intervillous space during a contraction, which is the hallmark of uteroplacental insufficiency. [2, 3, 16]
Question 2: According to the 2008 NICHD guidelines, which of the following defines a fetal heart rate acceleration for a fetus at 34 weeks gestation?
- An abrupt increase of at least 10 bpm above baseline, lasting at least 10 seconds.
- A gradual increase of at least 15 bpm above baseline, lasting at least 15 seconds.
- An abrupt increase of at least 15 bpm above baseline, lasting at least 15 seconds but less than 2 minutes. (Correct answer)
- Any increase above baseline that lasts for more than 2 minutes.
Correct answer: An abrupt increase of at least 15 bpm above baseline, lasting at least 15 seconds but less than 2 minutes.
For a fetus at 32 weeks of gestation or greater, an acceleration is defined as a visually apparent abrupt increase (onset to peak <30 seconds) in the FHR from the baseline. The peak must be at least 15 bpm above the baseline, and the duration must be at least 15 seconds but less than 2 minutes from the onset to the return to baseline. [5, 7, 10]
Question 3: A laboring patient's EFM tracing shows an abrupt FHR decrease from a baseline of 145 bpm to a nadir of 90 bpm. The onset of the deceleration to the nadir is less than 30 seconds. This change is best described as a:
- Late deceleration
- Variable deceleration (Correct answer)
- Early deceleration
- Prolonged deceleration
Correct answer: Variable deceleration
A variable deceleration is defined by its abrupt onset (onset to nadir in <30 seconds). It is a visually apparent decrease in the FHR of at least 15 bpm, lasting at least 15 seconds but less than 2 minutes. This pattern is typically caused by umbilical cord compression. [1, 5, 6]
Question 4: A clinician notes a visually apparent, smooth, sine wave-like undulating pattern in the FHR baseline with a frequency of 3-5 cycles per minute that persists for 25 minutes. This pattern is defined as a sinusoidal pattern and is a Category III tracing, often associated with which condition?
- Maternal fever
- Fetal sleep cycle
- Severe fetal anemia (Correct answer)
- Use of epidural analgesia
Correct answer: Severe fetal anemia
A true sinusoidal pattern is an ominous finding associated with high rates of fetal morbidity and mortality. It is most commonly linked with severe fetal anemia, which can result from conditions like Rh isoimmunization or significant fetal-maternal hemorrhage. [4, 9, 18]
Question 5: A fetal heart rate deceleration begins at a baseline of 130 bpm, drops to 80 bpm, and lasts for 4 minutes before returning to the previous baseline. According to NICHD guidelines, how should this event be classified?
- A new baseline of bradycardia
- A recurrent late deceleration
- A severe variable deceleration
- A prolonged deceleration (Correct answer)
Correct answer: A prolonged deceleration
A prolonged deceleration is defined as a decrease in the FHR from the baseline of at least 15 bpm, lasting for at least 2 minutes but less than 10 minutes. A deceleration lasting 10 minutes or more is considered a baseline change. [1, 7, 21]
Question 6: A series of accelerations are observed on a fetal monitoring strip that do not occur in conjunction with uterine contractions. These changes are best described as:
- Periodic
- Cyclical
- Episodic (Correct answer)
- Reactive
Correct answer: Episodic
The NICHD guidelines define periodic patterns as those associated with uterine contractions, while episodic patterns are those not associated with uterine contractions. Accelerations occurring independently of contractions are therefore classified as episodic. [4, 6, 21]
EFM - Electronic Fetal Monitoring Periodic and Episodic Changes Questions and Answers
A fetal heart rate tracing shows recurrent decelerations where the onset, nadir, and recovery are delayed relative to the beginning, peak, and end of the uterine contractions.
This pattern is most indicative of which underlying condition?