CTG Analysis

Question 1

Framework for analysing CTG?

Answer 1

DR C BRAVaDO

• DR ➔ Determining risk of the pregnancy
• C ➔ Contractions
• BR ➔ Baseline rate (110-160 bpm)
• A ➔ Accelerations
• Va ➔ Variability
• D ➔ Decelerations
• O ➔ Overall impression

Question 2

How do you describe contractions?

Answer 2

• X in 10 (how many contractions in a ten-minute period)
  
  • Around 3-4 in 10 occurs in labour
  • > 5 in 10 is concerning for uterine
    hyperstimulation
• Duration (last around 40-50s)
• Intensity (Assessed on palpations)

Question 3

What is the normal range for baseline rate?

Answer 3

110-160 bpm

Question 4

What does foetal tachycardia (>160) indicate?

Answer 4

• Chorioamnionitis (infection)
• Foetal hypoxia
• Foetal anaemia
• Premature
• Neonatal hyperthyroidism (child born to Graves mother, TRAbs pass through placenta)

Question 5

What does foetal bradycardia (<110) indicate?

Answer 5

• Post-date gestation
• Prolonged severe bradycardia (<80 for at least 3 mins):
  
  • Cord prolapse
  • Cord compression
  • Epidural/Spinal anaesthesia
  • Maternal seizure

Question 6

What is an acceleration?

Answer 6

• An abrupt increase of 15 bpm in baseline rate which remains elevated for >15 seconds
• Presence of accelerations is reassuring
• Accelerations occurring alongside uterine contractions is a sign of a healthy foetus.
• The absence of accelerations with an otherwise normal CTG is UNIMPORTANT

Question 7

What is variability?

Answer 7

• Variation of foetal heart rate from one beat to the next (e.g. one beat 120, next 130)
• A healthy foetus will constantly be adapting its heart rate in response to changes in its environment. (reactive)

Question 8

What is a normal range for variability?

Answer 8

5-25 bpm change per beat (either up or down)

Question 9

What causes reduced variability?

Answer 9

• Foetal sleeping (should not last longer than 40 mins)
• Foetal acidosis/hypoxia
• Maternal opiates and benzos

Question 10

What conservative measure can relieve a reduced variability

Answer 10

Re-position the mother

Question 11

What are decelerations?

Answer 11

• An abrupt decrease in baseline rate of 15 bpm which remains decreased for >15 seconds
• in the case of reduced variability, the decels may be shallow

Question 12

What do early decels represent?

Answer 12

• ↓ baseline rate start when the uterine contraction begins and
• Rapid recovery when uterine contraction stops.
• This is due to increased foetal intracranial pressure causing increased vagal tone.

Question 13

What do variable decels represent?

Answer 13

• ↓ baseline rate with a variable recovery phase.
• They are variable in their duration and may not have any relationship to uterine contractions
• Usually caused by cord compression

Question 14

What do late decels represent?

Answer 14

• Late decelerations begin at the peak of the uterine contraction and recover after the contraction ends (the whole time the uterus is contracting, the baby has shit blood flow)
• Indicates decreased uteroplacental blood flow
  
  • Maternal hypotension
  • Pre-eclampsia
  • Uterine hyperstimulation

Question 15

What are prolonged decels?

Answer 15

• A prolonged deceleration is defined as a deceleration that lasts more than 2 minutes:
• If it lasts between 2-3 minutes it is classed as non-reassuring.
• If it lasts longer than 3 minutes it is immediately classed as abnormal.

Question 16

What is a sinusoidal trace?

Answer 16

A sinusoidal HR wave which indicates foetal distress

Question 17

How to describe the Overall impression?

Answer 17

The overall impression can be described as either normal, suspicious (1 re-assuring) or pathological

Question 18

What makes a pathological CTG?

Answer 18

• at least one abnormal feature
• 2 or more non-reassuring features

Question 19

What features makes a non-reassuring CTG? (BR and Variability)

Answer 19

• BR 100-109
• BR 161-180
• variability <5 for 30-50 minutes (baby may be sleeping)
• variability >25 for 15-25 minutes

Question 20

What features make an abnormal CTG?

Answer 20

• BR <100
• BR >180
• Variability <5 for more than 50 mins
• Variability >25 for more than 25 mins
• Late decels occurring for >30 mins
• Prolonged deceleration occurring for >3 minutes
• Prolonged bradycardia occurring for >3 minutes
• Variable decels + concerning feature over >50% contractions <30 minutes
• Variable decels + concerning featureless <50% contractions >30 minutes
• Variable decels with no concerning features >90 minutes

Question 21

What to do if pathological CTG

Answer 21

• URGENT REVIEW by obstetrician and senior midwife
• Positional manoeuvres
• Expedite birth (Induction, C-section) if there has been a clear ACUTE EVENT (uterine rupture, abruption, cord compression)