Fetal Monitoring and Cardiotocography

Fetal Monitoring

Definition

• Cardiotocography (CTG) is a method of fetal monitoring that measures the fetal heart rate (FHR) and uterine contractions.

Indications

• High-risk pregnancies
• Fetal distress or growth restriction
• Multiple gestations
• Postdates pregnancy
• Oligohydramnios or polyhydramnios
• Abnormal fetal heart rate or rhythm

Components

• Fetal heart rate (FHR) monitoring
• Uterine contraction monitoring

FHR Patterns

• Baseline FHR: average FHR over a 10-minute period
• Variability: fluctuations in FHR around the baseline
• Accelerations: abrupt increases in FHR
• Decelerations: abrupt decreases in FHR
• Tachycardia: FHR > 160 bpm
• Bradycardia: FHR < 100 bpm

Electronic Monitoring

Definition

• Electronic fetal monitoring (EFM) uses electronic devices to record and display FHR and uterine contractions.

Methods

• External monitoring: uses a tocodynamometer to measure uterine contractions and a Doppler ultrasound to measure FHR
• Internal monitoring: uses a fetal scalp electrode to measure FHR and an intrauterine pressure catheter to measure uterine contractions

Advantages

• Continuous monitoring of FHR and uterine contractions
• Earlier detection of fetal distress
• Improved fetal outcomes

Limitations

• May not accurately detect fetal distress
• May lead to unnecessary interventions
• Requires skilled interpretation of tracings

Fetal Monitoring

Definition and Indications

• Cardiotocography (CTG) measures fetal heart rate (FHR) and uterine contractions in high-risk pregnancies, fetal distress, multiple gestations, postdates pregnancy, and oligohydramnios or polyhydramnios.

Components and FHR Patterns

• FHR monitoring and uterine contraction monitoring are the two components of CTG.
• FHR patterns include:
  • Baseline FHR: average FHR over 10 minutes.
  • Variability: fluctuations in FHR around the baseline.
  • Accelerations: abrupt increases in FHR.
  • Decelerations: abrupt decreases in FHR.
  • Tachycardia: FHR > 160 bpm.
  • Bradycardia: FHR < 100 bpm.

Electronic Fetal Monitoring

Definition and Methods

• Electronic fetal monitoring (EFM) uses devices to record and display FHR and uterine contractions.
• EFM methods include:
  • External monitoring: uses a tocodynamometer and Doppler ultrasound.
  • Internal monitoring: uses a fetal scalp electrode and intrauterine pressure catheter.

Advantages and Limitations

• Advantages of EFM:
  • Continuous monitoring of FHR and uterine contractions.
  • Earlier detection of fetal distress.
  • Improved fetal outcomes.
• Limitations of EFM:
  • May not accurately detect fetal distress.
  • May lead to unnecessary interventions.
  • Requires skilled interpretation of tracings.