CTG Interpretation in Fetal Monitoring

Overview of CTG Interpretation

CTG (Cardiotocography) interpretation is a critical component of fetal monitoring during pregnancy and labor. It involves analyzing the CTG tracing to identify normal or abnormal fetal heart rate patterns, which can indicate fetal well-being or distress.

Components of a CTG Tracing

• Baseline Fetal Heart Rate (FHR): The average FHR over a 10-minute segment, measured in beats per minute (bpm).
• Variability: The fluctuation in FHR over a 10-minute segment, measured in bpm.
• Accelerations: Transient increases in FHR above the baseline, typically in response to fetal movement.
• Decelerations: Transient decreases in FHR below the baseline, which can be early, late, or variable.

Normal CTG Patterns

• Reactive CTG: A normal tracing with a baseline FHR of 100-160 bpm, moderate variability (5-25 bpm), and presence of accelerations.
• Non-Reactive CTG: A tracing with a baseline FHR of 100-160 bpm, minimal variability (<5 bpm), and absence of accelerations.

Abnormal CTG Patterns

• Tachycardia: A baseline FHR >160 bpm, which can indicate fetal distress or maternal fever.
• Bradycardia: A baseline FHR <100 bpm, which can indicate fetal distress or maternal hypotension.
• Decelerations:
  • Early Decelerations: Uniform, symmetrical decelerations that coincide with uterine contractions, indicating head compression.
  • Late Decelerations: Uniform, symmetrical decelerations that occur after uterine contractions, indicating fetal distress.
  • Variable Decelerations: Irregular, asymmetrical decelerations that can indicate umbilical cord compression or fetal distress.

Interpretation Guidelines

• Three-Tier System:
  1. Reassuring: A normal, reactive CTG tracing.
  2. Non-Reassuring: A non-reactive CTG tracing with no decelerations.
  3. Abnormal: A CTG tracing with decelerations or other abnormal features.
• Actionable Decelerations: Decelerations that require immediate attention, such as late or variable decelerations.

Limitations of CTG Interpretation

• Interobserver Variability: Different clinicians may interpret the same CTG tracing differently.
• Technical Errors: Equipment malfunction or incorrect placement of electrodes can lead to inaccurate tracings.
• Maternal and Fetal Factors: Maternal fever, uterine hypertonus, and fetal anomalies can affect CTG interpretation.

CTG Interpretation

• Critical component of fetal monitoring during pregnancy and labor, involves analyzing CTG tracing to identify normal or abnormal fetal heart rate patterns.

Components of a CTG Tracing

• Baseline Fetal Heart Rate (FHR): average FHR over a 10-minute segment, measured in beats per minute (bpm).
• Variability: fluctuation in FHR over a 10-minute segment, measured in bpm.
• Accelerations: transient increases in FHR above the baseline, typically in response to fetal movement.
• Decelerations: transient decreases in FHR below the baseline, which can be early, late, or variable.

Normal CTG Patterns

• Reactive CTG: normal tracing with a baseline FHR of 100-160 bpm, moderate variability (5-25 bpm), and presence of accelerations.
• Non-Reactive CTG: tracing with a baseline FHR of 100-160 bpm, minimal variability (<5 bpm), which can indicate fetal distress or maternal fever.
• Bradycardia: baseline FHR <100 bpm.