Lecture on Fetal Heart Rate Patterns

Jul 12, 2024

Lecture on Fetal Heart Rate Patterns

Introduction

  • Presenter: Meris with Level Up RN
  • Topic: Fetal heart rate (FHR) patterns - normal and abnormal findings, causes, and interventions
  • Reference: Maternity Nursing Flashcards (Labor and Delivery section)

Normal Fetal Heart Rate Patterns

Baseline Heart Rate

  • Normal range: 110-160 bpm

Accelerations

  • Definition: Increase in FHR by at least 15 bpm, sustained for at least 15 seconds
  • Indications: Reassuring, indicates adequate oxygenation, occurs due to fetal movement, vaginal exams, etc.

Early Decelerations

  • Definition: Decrease in FHR in sync with contractions (mirror image of contraction)
  • Cause: Head compression
  • Significance: Benign, no intervention needed

Variability

  • Definition: Fluctuations in FHR by 6-25 bpm around baseline, indicating a healthy nervous system
  • Types: Various types (absent, minimal, marked, moderate)
  • Desired type: Moderate variability is reassuring

Abnormal Fetal Heart Rate Patterns

Fetal Bradycardia

  • Definition: FHR < 110 bpm sustained for ≥10 minutes
  • Causes: Prolonged cord compression, umbilical cord prolapse, anesthetic medications, fetal heart abnormalities
  • Interventions: Side-lying position, oxygen, IV fluids, notify provider, stay at bedside

Fetal Tachycardia

  • Definition: FHR > 160 bpm sustained for ≥10 minutes
  • Causes: Maternal fever/infection, fetal hypoxia, maternal hypothyroidism, cocaine use
  • Interventions: Treat underlying cause (e.g., antipyretics for fever), IV fluids, oxygen
  • Warning: Tachycardia with decreased variability indicates severe fetal distress

Late Decelerations

  • Definition: Deceleration with onset and nadir after the peak of the contraction
  • Cause: Uteroplacental insufficiency (placental insufficiency)
  • Interventions: LION (Left-lying, IV fluids, Oxygen, Notify provider), prepare for surgery (C-section) if unresolved

Variable Decelerations

  • Definition: Sharp, dramatic drop in FHR, often resembling the letter 'V'
  • Cause: Umbilical cord compression
  • Interventions: Trendelenburg position, knee-chest position, oxygen, discontinue oxytocin, notify provider, amnioinfusion for conditions like oligohydramnios

Mnemonic for FHR Patterns

VEAL CHOP

  • Variable deceleration: Cord compression
  • Early deceleration: Head compression
  • Accelerations: Okay (reassuring)
  • Late decelerations: Placental insufficiency

Quiz Questions

  1. What is the normal baseline for FHR?
  2. For which FHR pattern would you place the mother in Trendelenburg or knee-chest position?
  3. What does moderate variability in FHR indicate about the fetus?
  4. What is the cause of late decelerations?