Electronic Fetal Monitoring (EFM) Essentials

Electronic Fetal Monitoring (EFM) Essentials

EFM Overview

• EFM is an ongoing, indirect screening tool for fetal oxygenation not diagnostic tool.

• Fetal heart rate (FHR) changes detect interruptions in fetal oxygenation.

Factors Affecting Uterine Blood Flow

• Excessive uterine activity(mom having contractions to low or too frequent)

• Maternal hypotension or hypertension(can cause seizures in mom) .

• Placental changes: calcifications, degenerative changes, infarction(abruption where it can tears from the wall/ if it does the baby has no oxygen!!) , decreased surface area.

• Infection (Chorioamnionitis) and edema.

EFM Components

• External: Ultrasound (measures FHR), Tocodynamometer (measures contraction frequency).

• Internal: Intrauterine Pressure Catheter (IUPC) (measures uterine activity internally), Fetal Scalp Electrode (FSE) (measures FHR internally).

Reading EFM Paper

• Dark lines: $1$ minute intervals.

• Lighter lines: $10$ second intervals.

• Vertical FHR boxes: $10$ beats each.

• Vertical contraction boxes: $5$ mmHg each.

FHR Characteristics

FHR Baseline

• Normal range: $110-160$ bpm.

• Approximate mean FHR rounded to increments of $5$ bpm over a $10$-minute window.

FHR Variability

• Most important predictor of adequate fetal oxygenation.

• Absent: Undetectable; associated with risk for fetal metabolic acidemia, requires prompt evaluation.

• Minimal: Detectable but $\leq 5$ bpm; may indicate fetal hypoxemia if prolonged.

• Moderate: Range $6-25$ bpm; indicative of fetal well-being and adequate oxygenation.

  • this is what we want!! very happy baby!

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• Marked: Range > 25 bpm; rare, often considered benign.

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• Sinusoidal Pattern: A smooth, sine wave-like undulating pattern ($3-5$ cycles/minute for $\geq 20$ minutes) without accelerations; very concerning.

• Absent Variability: No detectable changes in fetal heart rate; typically associated with fetal distress and requires immediate evaluation. NEVER WANT TO SEE STRAIGHT LINES!!!!!

  • its normal for it to happen for a little bit because mom just got some medication but if it is greater than or equal to $30$ bpm, it could indicate potential complications that need to be addressed promptly.

FHR Accelerations

• Abrupt increase in FHR ( < 30 seconds to peak, lasting < 2 minutes).

• $\geq 32$ weeks gestational age: $\geq 15$ bpm increase for $\geq 15$ seconds ($15 \times 15$ rule).

• < 32 weeks gestational age: $\geq 10$ bpm increase for $\geq 10$ seconds ($10 \times 10$ rule).

FHR Decelerations (VEAL CHOP)

• Variable: Cord compression; abrupt decrease.

  • If you notice this CHANGE THE POSITION!

• Early: Head compression; gradual decrease/return, symmetrical, peaks with contraction.

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• Acceleration: Okay/Oxygenation.

• Late: Placental insufficiency; gradual decrease/return, occurs after peak of contraction. 

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FHR Tracing Categories

• Category I (Normal): Baseline $110-160$ bpm, moderate variability, no late or variable decelerations, accelerations present/absent, early decelerations present/absent

• Category II (Indeterminate): Characteristics not Category I or III ; may include baseline heart rate between $110-160$ bpm with decreased variability, variable decelerations that are intermittent, and/or transient late decelerations.

• Category III (Abnormal): Absent variability with recurrent late or variable decelerations or bradycardia; or sinusoidal pattern.

  • end up in the OR (immediate delivery)

Non-Stress Testing (NST)

• Assesses fetal well-being in response to activity.

• Reactive NST: At least $2$ accelerations in $20$ minutes for fetuses $\geq 32$ weeks gestation, with normal baseline, moderate variability, and no late decelerations.

FHR Bradycardia and Tachycardia

• Bradycardia: Baseline < 110 bpm for > 10 minutes

  • profound bradycardia (< 60 bpm) is an emergency (CPR).

  • external recessitation: should be initiated immediately to maintain fetal oxygenation and prevent long-term complications.

    • moving mom around

    • prolapse

    • uterine rupture

    • cord compression may occur during labor, which can lead to fetal distress and requires careful management to ensure the safety of both mother and baby.

    • significant abdonimal pain

    • hard abdomen other than a contraction?

      • will complain with severe abdominal pain

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• Tachycardia: Baseline > 160 bpm for > 10 minutes; common causes include maternal fever, medications.

Intrauterine Resuscitation (Golden Rules)

change position, iv bolus and call provider

• you can hit stop on the pitocin while waiting for the provider

1. Maternal Repositioning (lateral- left to right)

2. IV Fluid Bolus.

3. Oxygen Administration (no longer routinely recommended; discontinue based on fetal response).

Uterine Activity Assessment

• Frequency: Beginning of one contraction to the beginning of the next; Average number of contractions in $10$ minutes over $30$-minute period (> 5 contractions in $10$ minutes = tachysystole: not enough resting time).

• Duration: Length of contraction in seconds.

• Intensity: Assessed by palpation (mild, moderate, strong) or in mmHg (IUPC: the most accurate).

• Resting Tone: Between contractions; assessed by palpation (soft, hard) or in mmHg (IUPC).

  • very important since we need to oxygenate the baby

• Montevideo Units (MVUs): Quantifies uterine activity with an IUPC; sum of (peak intensity - resting tone) for contractions over $10$ minutes. Adequate labor: $\geq 200$ MVUs.

  • peak minus the resting tone= to give you the MVU

• Tachysystole: > 5 contractions in $10$ minutes; reduces maternal-fetal gas exchange and requires intervention (repositioning, fluid bolus, adjust Pitocin, tocolytics).

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