Fetal Heart Rate Patterns

Overview

• Objective: Discuss normal and abnormal fetal heart rate (FHR) patterns, their causes, and interventions.
• Reference: Maternity Nursing Flashcards - Labor and Delivery section by Level Up RN.

Normal Fetal Heart Rate Patterns

Baseline Heart Rate

• Normal Range: 110 - 160 beats per minute (bpm).

Accelerations

• Definition: Increase in FHR by at least 15 bpm, lasting for at least 15 seconds.
• Significance: Indicates good oxygenation, typically occurs with fetal movement or stimulation (e.g., vaginal exams).
• Interpretation: Reassuring and normal.

Early Decelerations

• Definition: Deceleration mirrors the contraction (in sync with the contraction's peak).
• Cause: Head compression.
• Significance: Benign, no intervention needed.

Variability

• Definition: Fluctuations in FHR of 6-25 bpm around the baseline.
• Indication of: Healthy fetal nervous system.
• Types: Moderate variability is reassuring.

Abnormal Fetal Heart Rate Patterns

Fetal Bradycardia

• Definition: FHR < 110 bpm for ≥ 10 minutes.
• Causes: Prolonged cord compression, umbilical cord prolapse, anesthetic medications, fetal heart abnormalities.
• Intervention:
  • Reposition to side-lying.
  • Administer oxygen and IV fluids.
  • Notify provider and stay with the mother.

Fetal Tachycardia

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

Late Decelerations

• Definition: Deceleration occurs after the contraction peak, with a prolonged return to baseline.
• Cause: Uteroplacental insufficiency.
• Intervention (LION):
  • L: Left-lying position.
  • I: IV fluids.
  • O: Oxygen and discontinue oxytocin.
  • N: Notify provider.
  • S: Prep for surgery if unresolved.

Variable Decelerations

• Definition: Sharp drop and quick recovery in FHR.
• Cause: Umbilical cord compression.
• Intervention:
  • Reposition to Trendelenburg or knee-chest.
  • Administer oxygen and discontinue oxytocin.
  • Notify provider.
  • Consider amnioinfusion in cases of oligohydramnios.

Mnemonic: VEAL CHOP

• Variable – Cord compression.
• Early – Head compression.
• Accelerations – Okay.
• Late – Placental insufficiency.

Quiz Questions

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