CTG

Question 1

What is a CTG

Answer 1

Cardiotocography
It measures the foetal heart rate and maternal heart rate and contractions

Note - The contractions are merely measured for when they were and for how long (to check intensity - check with the patient and palpate during a contraction)

Question 2

CTG interpretation steps

Answer 2

Check patient details
Chest gestation

DR C BRAVADO

DR - Define risk (high/ low risk)
C - Contractions - how many are present in 10 mins (are they present? - if so, note duration and intensity)
BRa - Baseline Rate (normal foetal HR 110-160, normal maternal HR in pregnancy 70-112)
V - Variability (normal = 5-25bpm)
A - Accelerations (+ at the same time as contraction?)
D - Deceleration (+ at the same time as contraction?)
O - Overall Impression + STV

Question 3

Contractions

Answer 3

Could be labour/ braxton hicks (check with patient’s level of intensity and by palpating during contraction)
Early labour - can be less regular

Question 4

Baseline rate

Answer 4

Hypoxia could show as tachycardia (mild) or severe prolonged bradycardia (severe)

Bradycardia is normal if gestation post-date

Severe prolonged bradycardia = <80 for >3mins
Causes:
- Prolonged cord compression
- Cord prolapse
- Maternal seizure
- Epidural

Question 5

Variability

Answer 5

Reassuring = 5-25bmp
Non-reassuring = <5 30-50mins / >25 15-25mins
Abnormal = <5 50mins/ >25 25mins

Foetus may be asleep (usually 40mins)
Reduced supply due to parent lying on their back (lie on the left to improve variability)

Causes:
foetal acidosis + hypoxia
foetal tachycardia
drugs (opioids/ benzodiazepines/ methyldopa/ magnesium sulphate)
prematurity

Question 6

Accelerations

Answer 6

Usually all normal - sign that baby is adapting to the environment and maintaining haemostasis

Question 7

Decelerations

Answer 7

Normal if alongside contractions and the HR recovers
Causes for concern - hypoxic distress

Variable deceleration: usually due to cord compression in labour (normal if with shoulders = HR acceleration -> deceleration -> normalises)

Late decelerations: (deceleration starts at peek contraction) = reduced blood flow

Prolonged deceleration: (takes >3mins to recover)

Sinusoidal: (rare) = severe hypoxia/ an anaemia/ haemorrhage

Question 8

STV

Answer 8

Computer programming to check for abnormalities on a CTG (cCTG)
Based on the Dawes-Redman criteria
Abnormal for different gestations =
26 - 28+6 <2.6
29 - 31+6 <3
32 - 33.6 <3.5
34 - labour <4.5