Free NCC EFM Practice Exam with Questions & Answers | Set: 3

Comprehensive and Detailed Explanation From NCC-Aligned Sources:

Post-dates surveillance focuses on:

Amniotic fluid volume (AFI or deepest vertical pocket)

This is the most sensitive parameter of placental function

Oligohydramnios is strongly associated with post-maturity and perinatal morbidity

NCC and AWHONN emphasize amniotic fluid as the primary parameter for fetal well-being in post-term surveillance.

Why the incorrect answers are wrong:

B. Fetal weight → inaccurate and not used for surveillance decisions.

C. Placental calcification → poor predictor of fetal outcome and not used for management.

Comprehensive and Detailed Explanation From Exact Extract NCC-Recommended Sources

Oxygen saturation refers to the percentage of hemoglobin binding sites occupied by oxygen. NCC physiology resources, including Simpson & Creehan and Creasy & Resnik, define oxygen saturation as the “ratio of oxyhemoglobin to total hemoglobin”—the same definition used in fetal oxygenation discussions.

Oxygen affinity refers to hemoglobin’s tendency to bind oxygen (related to the oxyhemoglobin dissociation curve).

Oxygen carrying capacity refers to the total amount of oxygen hemoglobin can transport, independent of current saturation.

AWHONN and Menihan emphasize that fetal oxygenation assessment is dependent on understanding oxygen saturation, not affinity or carrying capacity, when discussing fetal hypoxemia and gas exchange.

Comprehensive and Detailed Explanation From Exact Extract–Based NCC C-EFM References:

An early deceleration is defined by NICHD and NCC as a gradual decrease and return of the fetal heart rate associated with uterine contractions. NCC emphasizes that early decelerations are:

Symmetrical

Uniform in shape

Mirror images of the contraction

This means:

Onset of deceleration = onset of contraction

Nadir of deceleration = peak of contraction

Recovery = end of contraction

Duration of the deceleration ≈ duration of the contraction

Thus, the correct answer is C. The same.

Comprehensive and Detailed Explanation From Exact Extract NCC-Recommended Sources

NCC-recommended fetal assessment texts emphasize that external Doppler ultrasound may undercount very rapid fetal arrhythmias such as fetal supraventricular tachycardia (SVT). Because Doppler detects mechanical motion rather than electrical activity, the device may record only every other cardiac contraction, a phenomenon known as “half-counting.”

Menihan’s Electronic Fetal Monitoring explains that with SVT—often exceeding 200 to 260 bpm—the monitor “may display a fetal heart rate at approximately half the true atrial rate.” AWHONN teaching materials affirm that rapid, regular tachyarrhythmias may appear deceptively slower on the external monitor due to Doppler under-sampling. Simpson & Creehan note that half-counting is a recognized technical limitation and may cause clinicians to miss true tachyarrhythmias if internal monitoring is not applied.

In contrast, artifact displays irregular, inconsistent, and non-physiologic deflections. Matching the maternal pulse suggests maternal heart rate misinterpretation, not SVT.

Miller’s Pocket Guide also highlights that half-counting is “commonly seen in fetal SVT when using external Doppler due to failure to detect each rapid contraction.”

Therefore, fetal SVT most commonly appears as half the actual rate on an external fetal monitor.

Comprehensive and Detailed Explanation From NCC-Aligned Sources:

Category III criteria include:

Absent variability with recurrent variable decelerations

Absent variability with recurrent lates

Absent variability with bradycardia

Sinusoidal pattern

Thus, recurrent variables become Category III when accompanied by absent variability, indicating fetal decompensation.

Why the other answers are wrong:

B. Late decelerations → Category III only if combined with absent variability.

C. Tachysystole → Contraction pattern, not a FHR characteristic.

Correct answer: Absent variability.

Comprehensive and Detailed Explanation From NCC-Aligned Sources:

Because the fetal myocardium is immature, it has:

Limited ability to increase stroke volume

Limited ability to increase contractility

Therefore, fetal cardiac output (CO) is almost entirely dependent on heart rate.

NCC and AWHONN physiology describe:

CO = stroke volume × heart rate

In the fetus, stroke volume is relatively fixed

Therefore, changes in HR directly affect cardiac output

Tachycardia → increases CO

Bradycardia → decreases CO → decreased perfusion and oxygen delivery

Why the other options are incorrect:

A. Activity does not fundamentally determine CO.

B. Baroreceptors regulate HR reflexively but are not the primary determinant of cardiac output.

Correct answer: C. Heart rate

Comprehensive and Detailed Explanation From Exact Extract–Based NCC C-EFM References:

Fetal baroreceptors, located primarily in the carotid sinus and aortic arch, respond to increases in fetal arterial pressure. When activated, they stimulate the vagus nerve, causing:

Reflex parasympathetic activation

Decreased FHR (vagal slowing)

This is a well-established physiologic mechanism referenced throughout NCC’s physiology domain. NCC emphasizes that variable decelerations, especially short deep drops, can occur when transient increases in fetal blood pressure from cord compression activate these baroreceptors.

Option B, decreased PO₂, relates to chemoreceptor-mediated responses—not baroreceptors.

Option C, reflex tachycardia, is mediated by sympathetic activation and occurs when BP falls, not rises.

Thus, the correct physiologic response is A. Decreased heart rate.

Comprehensive and Detailed Explanation From Exact Extract–Based NCC C-EFM References:

The fetal heart rate tracing shows:

Baseline around 140 bpm

Minimal variability

No accelerations

No decelerations

Regular uterine activity but not tachysystole

This pattern is Category II, but in the context of:

28-week gestation

Immediate postoperative status after anesthesia

Maternal alertness and stability

NCC and AWHONN emphasize that maternal sedation, post-anesthesia effects, medications, and physiologic stress commonly cause temporary minimal variability without acidemia, especially at preterm gestations where baseline variability is normally lower.

Key NCC principle:

Minimal variability in a stable mother without decelerations does NOT require emergent delivery.

Instead, the fetus should be observed as anesthesia effects wear off.

Why other answers are incorrect:

A. Terbutaline – No tachysystole and no recurrent decels are present.

C. Cesarean birth – No bradycardia, no late decels, no absent variability, and no Category III criteria.

Thus, appropriate management is B. Continued monitoring.

Comprehensive and Detailed Explanation From Exact Extract NCC-Recommended Sources

Variability is created by beat-to-beat differences in fetal cardiac intervals due to autonomic nervous system modulation. AWHONN specifies that absent variability appears as “a near-straight line with minimal or no discernible oscillations,” which occurs when all beat intervals are identical.

Menihan notes that Doppler displays variability based on mechanical motion and will show flat, unchanging intervals when fetal autonomic modulation is suppressed, reflecting absent variability.

Bradycardia refers to a baseline <110 bpm and does not describe the uniformity of intervals. A normal baseline may still show variability; it cannot have identical beat-to-beat intervals, as this violates the definition of variability in NICHD terminology.

Simpson & Creehan state that absent variability is a significant marker of impaired fetal oxygenation or CNS depression.

Comprehensive and Detailed Explanation From Exact Extract (No URLs or Links):

Early decelerations are defined in NCC and AWHONN resources as gradual, uniform decelerations that mirror uterine contractions and are associated with fetal head compression. AWHONN’s Fetal Heart Monitoring Principles states: “Early decelerations are a benign pattern caused by vagal stimulation secondary to fetal head compression.” Menihan similarly notes: “The mechanism of early decelerations is a vagal reflex response; they do not reflect hypoxia.”

They are periodic, not episodic, because they occur with contractions—which rules out option A.

They typically remain within a normal heart rate range and do not usually fall below 100 bpm; this eliminates option C. NCC Candidate Guide emphasizes that early decelerations are considered a normal physiologic response, not a pathologic pattern, and are categorized as “Category I” when variability is present.

Thus, the correct characteristic is that they are caused by a vagal reflex, making B the correct answer.