ctg(cardiotocography)

How CTG Works

• External CTG:Two transducers are placed on the mother’s abdomen—one records the fetal heart rate using ultrasound, and the other monitors uterine contractions using tocodynamometry. The data are displayed as continuous traces on a paper or digital printout.
• Internal CTG:In some cases during labor, a small electrode may be attached to the baby’s scalp to directly record the heart rate, especially if external monitoring is unreliable.

What CTG Measures

• Fetal Heart Rate (FHR):Baseline rate (normal: 110–160 bpm), variability, accelerations, and decelerations.
• Uterine Contractions:Frequency, duration, and intensity.
• Fetal Movements:Sometimes recorded by the mother pressing a button when the baby moves.

Clinical Uses

• Antenatal (before labor):Screening for fetal hypoxia (lack of oxygen), especially in high-risk pregnancies (e.g., diabetes, hypertension, growth restriction).
• Intrapartum (during labor):Continuous monitoring to detect fetal distress and guide decisions about interventions (e.g., need for cesarean or assisted delivery).

Interpretation

• Normal (Reactive) CTG:Baseline FHR 110–160 bpm, good variability (>5 bpm), at least two accelerations >15 bpm for 15 seconds in 20 minutes, no decelerations.
• Abnormal CTG:Reduced variability, persistent decelerations, or abnormal baseline may indicate fetal distress and require prompt evaluation and intervention.

Advantages

• Non-invasive and safe
• Provides continuous, objective data
• Helps identify fetuses at risk of hypoxia or distress

Limitations

• Should not be used in isolation for decision-making; always consider the overall clinical picture.
• May restrict maternal mobility during labor.
• False positivescan occur, sometimes leading to unnecessary interventions.