Fetal Monitoring Techniques

Fetal Monitoring Techniques - Initial Peeks

• Purpose: Evaluate fetal oxygenation & well-being during labor to detect hypoxia.
• Core Methods:
  • Intermittent Auscultation (IA): Using Pinard or Doppler device.
  • Electronic Fetal Monitoring (EFM): Continuous Cardiotocography (CTG).

⭐ Intermittent auscultation (IA) is suitable for low-risk labor; continuous EFM (CTG) is for high-risk cases or if IA is abnormal.

Fetal Monitoring Techniques - Heart's Language

• Assesses fetal well-being during labor. Key: Cardiotocography (CTG).
• CTG Components:
  • Baseline Fetal Heart Rate (FHR): Normal 110-160 bpm.
  • Variability: Beat-to-beat FHR fluctuations.
    • Absent: Undetectable.
    • Minimal: <5 bpm.
    • Moderate: 5-25 bpm (reassuring).
    • Marked: >25 bpm.
  • Uterine Contractions: Frequency, duration.
  • Accelerations: Transient ↑ FHR by ≥15 bpm for ≥15 sec (reassuring).
  • Decelerations: Transient ↓ FHR (early, late, variable, prolonged).

⭐ Moderate variability (5-25 bpm) is the most reliable indicator of fetal oxygenation and an adequately functioning fetal CNS.

Fetal Monitoring Techniques - Rises & Dips

• Accelerations: Abrupt FHR ↑ (≥15 bpm for ≥15s if ≥32wks; ≥10 bpm for ≥10s if <32wks). Reassuring.
• Decelerations:
  • Early: Gradual ↓, mirrors contraction. Cause: Head compression. Benign.
  • Late: Gradual ↓, nadir after contraction peak. Cause: Uteroplacental insufficiency. Ominous.
  • Variable: Abrupt ↓ (<30s onset to nadir), V/U/W shape. Cause: Cord compression.
  • Prolonged: ↓ FHR ≥15 bpm, lasts 2-10 min.
• 📌 Mnemonic - VEAL CHOP:
  • Variable → Cord Compression
  • Early → Head Compression
  • Acceleration → OK
  • Late → Placental Insufficiency

⭐ Recurrent late decelerations signify uteroplacental insufficiency and are the most ominous pattern, strongly associated with fetal hypoxemia and acidosis.

Fetal Monitoring Techniques - FIGO's Verdict

The International Federation of Gynecology and Obstetrics (FIGO) 2015 guidelines provide a crucial three-tier classification system (Normal, Suspicious, Pathological) for Cardiotocography (CTG) interpretation. This system, based on assessing four primary CTG features, standardizes fetal monitoring during labor and guides management decisions.

• Baseline FHR: 110-160 bpm
• Variability: 5-25 bpm
• Decelerations: Type & frequency
• Accelerations: Presence

⭐ A sinusoidal pattern on CTG, characterized by smooth, regular oscillations, is a pre-terminal sign often linked to severe fetal anemia or asphyxia.

Fetal Monitoring Techniques - Deeper Dives

• Fetal Scalp Blood Sampling (FSBS):
  • pH/lactate for acidosis if CTG unclear.
  • Avoid: infections, bleeding risk, <34 wks.
• Fetal ECG (STAN): ST-analysis for hypoxia; CTG adjunct.
• Vibroacoustic Stimulation (VAS): Evokes FHR acceleration.

⭐ Fetal scalp blood pH < 7.20 or lactate > 4.8 mmol/L are critical thresholds indicating significant fetal acidosis, warranting immediate delivery.

High‑Yield Points - ⚡ Biggest Takeaways

• Baseline FHR: 110-160 bpm; moderate variability (6-25 bpm) is reassuring.
• Accelerations (↑15 bpm, ≥15s post-32wks) are signs of fetal well-being.
• Early decelerations indicate head compression; late decelerations signal uteroplacental insufficiency.
• Variable decelerations result from cord compression; often resolve with maternal position change.
• Sinusoidal pattern is ominous, associated with severe fetal anemia or hypoxia.
• Reactive NST: ≥2 accelerations (15x15) in 20 minutes.
• Biophysical Profile (BPP): Score 8-10 is normal; assesses NST, breathing, movement, tone, AFI (Amniotic Fluid Index).