Chapter 1-8: Intrapartum Fetal Monitoring and Heart Rate Tracings

Vocabulary flashcards covering intrapartum fetal heart rate monitoring concepts, deceleration interpretations, strip classifications, and clinical interventions from Chapters 1 through 8.

TOCO Transducer

An external monitor placed on top of the uterine fundus that measures the pressure, frequency, and duration of uterine contractions.

Ultrasound Transducer

An external monitor placed on the maternal abdomen over the fetal back to monitor the fetal heart rate.

Intrauterine Pressure Catheter (IUPC)

An internal monitor inserted into the uterine cavity between the fetal head and the uterus to measure the exact strength of contractions in Montevideo units and uterine resting tone.

Fetal Scalp Electrode (FSE)

An internal fetal monitor with a small metal corkscrew attached superficially into the scalp of the fetus to directly record the fetal heart rate.

Contraction Frequency

The timing measured from the beginning of one uterine contraction to the beginning of the next uterine contraction.

Contraction Duration

The length of time a single uterine contraction lasts, measured from the start of the contraction to its end (typically $60\text{--}90\,\text{seconds}$).

Montevideo Units (MVUs)

A quantitative measurement of uterine contraction strength and total intensity over a $10\,\text{minute}$ window, obtainable only via an intrauterine pressure catheter (IUPC).

Baseline Fetal Heart Rate

The average fetal heart rate rounded to increments of $5\,\text{bpm}$ during a $10\,\text{minute}$ segment, excluding accelerations and decelerations; normal baseline is $110\text{--}160\,\text{bpm}$ for a term infant.

Periodic Changes

Fluctuations or changes in the baseline fetal heart rate that occur in direct association with uterine contractions.

Episodic Changes

Fluctuations or changes in the baseline fetal heart rate that are not associated with uterine contractions.

Hypoxemia

A deficiency of oxygen in the arterial blood that can lead to fetal metabolic acidosis and asphyxia if uncorrected.

Novi System

A wireless, cord-free external monitoring system consisting of a central pod and four adhesive patches placed on the maternal abdomen.

Amnioinfusion

The instillation of isotonic fluid (such as normal saline) into the uterine cavity through an IUPC to cushion the umbilical cord and relieve severe variable decelerations.

Absent Variability

An amplitude range in the fetal heart rate baseline that is visually undetectable or completely flat.

Minimal Variability

An amplitude range in the fetal heart rate baseline of less than or equal to $5\,\text{bpm}$.

Moderate Variability

An amplitude range in the fetal heart rate baseline of $6\text{--}25\,\text{bpm}$, which is normal and highly predictive of a normal fetal acid-base balance.

Marked Variability

An amplitude range in the fetal heart rate baseline greater than $25\,\text{bpm}$.

Sinusoidal Pattern

A regular, smooth, undulating wave-like baseline fetal heart rate pattern associated with severe fetal anemia, chorioamnionitis, fetal sepsis, or maternal opioid use.

Fetal Tachycardia

A baseline fetal heart rate greater than $160\,\text{bpm}$ lasting for longer than $10\,\text{minutes}$.

Fetal Bradycardia

A baseline fetal heart rate less than $110\,\text{bpm}$ lasting for longer than $10\,\text{minutes}$.

Fetal Heart Rate Acceleration

A visually apparent abrupt increase in fetal heart rate reaching a peak of at least $15\,\text{bpm}$ above baseline and lasting at least $15\,\text{seconds}$ for term infants ($10\text{--}10$ for infants under $32\,\text{weeks}$).

Reactive Non-Stress Test (NST)

A fetal heart rate tracing containing at least two $15 \times 15$ accelerations within a $10\,\text{minute}$ window, indicating reassuring fetal oxygenation.

VEAL CHOP

A diagnostic mnemonic linking deceleration types to etiology: Variable = Cord compression, Early = Head compression, Acceleration = Okay, Late = Placental insufficiency.

Early Deceleration

A visually apparent gradual decrease and return of fetal heart rate associated with a contraction, where the lowest point (nadir) mirrors the peak of the contraction, caused by fetal head compression.

Late Deceleration

A visually apparent gradual decrease and return of fetal heart rate associated with a contraction, where the nadir occurs after the peak of the contraction, caused by uteroplacental insufficiency.

Variable Deceleration

A visually apparent abrupt drop in fetal heart rate (onset to nadir less than $30\,\text{seconds}$) shaped like a U or V, caused by umbilical cord compression.

Shoulder (Fetal Heart Rate)

A temporary compensatory acceleration of the fetal heart rate immediately preceding or following a variable deceleration.

Prolonged Deceleration

A visual drop in fetal heart rate below baseline lasting $2\,\text{minutes}$ or longer, but less than $10\,\text{minutes}$.

Terbutaline

A tocolytic medication administered to relax the uterus and decrease contraction frequency during uterine tachysystole.

Category I FHR Tracing

A normal fetal heart rate tracing with a baseline of $110\text{--}160\,\text{bpm}$, moderate variability, no late or variable decelerations, and optional accelerations or early decelerations.

Category II FHR Tracing

An indeterminate fetal heart rate tracing requiring evaluation and continued monitoring, characterized by features such as minimal variability, baseline tachycardia, or periodic decelerations.

Category III FHR Tracing

An abnormal fetal heart rate tracing requiring prompt medical intervention, characterized by absent baseline variability accompanied by recurrent late decelerations, recurrent variable decelerations, bradycardia, or a sinusoidal pattern.