EFM - Electronic Fetal Monitoring Baseline Fetal Heart Rate Questions and Answers

Question 1

According to the 2008 NICHD guidelines, what is the minimum amount of identifiable baseline that must be present in a 10-minute window to determine the baseline fetal heart rate?

Accepted Answer

At least 2 minutes, which do not need to be contiguous.

Answer

The National Institute of Child Health and Human Development (NICHD) guidelines specify that the baseline fetal heart rate is determined over a 10-minute window. To establish the baseline, there must be at least 2 minutes of identifiable baseline segments. These segments do not need to be continuous. If this minimum cannot be identified, the baseline is considered indeterminate.

Question 2

A term fetus has a baseline heart rate of 175 bpm that persists for more than 10 minutes. Which of the following is the correct classification for this baseline?

Accepted Answer

Tachycardia

Answer

Fetal tachycardia is defined as a baseline fetal heart rate greater than 160 bpm lasting for 10 minutes or longer. A normal baseline is 110-160 bpm. Bradycardia is a baseline less than 110 bpm. A prolonged acceleration is an increase in FHR that lasts for 2 minutes or more but less than 10 minutes; if it lasts 10 minutes or more, it is considered a change in baseline.

Question 3

A laboring patient's EFM tracing shows a consistent fetal heart rate of 100 bpm for the past 12 minutes, accompanied by moderate variability. Which of the following is the most likely cause for this fetal heart rate pattern?

Accepted Answer

Post-term gestation with mature parasympathetic nervous system

Answer

Fetal bradycardia is a baseline FHR less than 110 bpm. In a post-term fetus, increased vagal tone due to a mature parasympathetic nervous system can cause the baseline rate to be at the lower end of normal or mildly bradycardic. The presence of moderate variability makes severe, acute hypoxia (as seen with a cord prolapse) less likely. Maternal fever typically causes tachycardia, and while an arrhythmia could be a cause, parasympathetic maturity is a more common physiological reason for this specific pattern in a term or post-term fetus.

Question 4

A clinician is reviewing a 10-minute electronic fetal monitoring strip. For 7 minutes, the tracing is obscured by artifact. In the remaining 3 minutes, there are two separate 90-second segments of stable heart rate at 140-145 bpm without significant periodic changes. How should the baseline FHR be documented?

Accepted Answer

145 bpm

Answer

To determine the baseline, there must be at least 2 minutes (120 seconds) of identifiable baseline segments in a 10-minute window. In this scenario, there are two 90-second segments, totaling 180 seconds (3 minutes) of identifiable baseline. The mean FHR is approximated to the nearest 5 bpm increment. Since the rate is stable at 140-145 bpm, it would be rounded to 145 bpm.

Question 5

Which of the following would NOT be included when determining the baseline fetal heart rate?

Accepted Answer

Periods of marked variability

Answer

The baseline fetal heart rate is the mean FHR rounded to increments of 5 bpm during a 10-minute segment, EXCLUDING accelerations, decelerations, and periods of marked variability (>25 bpm amplitude). Segments with minimal or moderate variability between periodic changes are used to determine the baseline.

EFM - Electronic Fetal Monitoring Practice Test

EFM - Electronic Fetal Monitoring Practice Test

EFM - Electronic Fetal Monitoring Baseline Fetal Heart Rate Questions and Answers