CTG

Question 1

What is a CTG?

Answer 1

Cardiotocograph - this measures foetal heart rate in relation to contractions.

Question 2

How do we assess a CTG?

Answer 2

DR C BRAVADO

Question 3

Define DR C BRAVADO

Answer 3

DR- Define risks
C- contractions
BRa- Baseline rate 
V- variability
A- accelerations
D-decelerations
O-overall

Question 4

What is the range of baseline rate for a foetus?

Answer 4

110-160 bpm

Question 5

As the foetus grows and reaches older gestational age, what happens to its BRa?

Answer 5

It decreases, as it usually does in humans

Question 6

What is an acceptable variability?

Answer 6

5-25 beats

Question 7

What are accelerations?

Answer 7

Upward deflections in the foetal HR of 15 beats or more than the BRa for more than 15 seconds.

Question 8

What are decelerations?

Answer 8

Downwards deflections in foetal HR of 15 beats or more than the BRa for more than 15 seconds.

Question 9

What are the types of decelerations?

Answer 9

Early, late and variable

Question 10

What is an early deceleration?

Answer 10

A deceleration that occurs during the contraction

Question 11

What is a late deceleration?

Answer 11

A deceleration that occurs after the contraction

Question 12

What is variable deceleration?

Answer 12

Decelerations that occur as a mixture of both early and late. This is a rapid fall in BRa with a variable recovery.

Question 13

What can cause foetal tachycardia?

Answer 13

• Foetal hypoxia
• Chorioamnionitits
• Hyperthyroidism
• Foetal or maternal anaemia
• Foetal tachyarrythmia

Question 14

What can cause foetal bradycardia?

Answer 14

• Postdate gestation

- OP or OT presentation

Question 15

What are the characteristics of prolonged severe bradycardia?

Answer 15

Less than 80bpm for more than 3 minutes

Question 16

What can cause prolonged severe bradycardia?

Answer 16

• Prolonged cord compression
• Cord prolapse
• Epidural/spinals
• Maternal seizure
• Rapid foetal descent

Question 17

How can variability be categorised?

Answer 17

Reassuring
Non-reassuring
Abnormal

Question 18

Define reassuring variability

Answer 18

5-25 bpm

Question 19

Define non-reassuring variability

Answer 19

• Less than 5bpm for 30-50 minutes

- More than 25 bpm for 15-25 minutes

Question 20

Define abnormal variability

Answer 20

• Less than 5 bpm for more than 50 minutes
• More than 25 bpm for more than 25 minutes
• Sinusoidal

Question 21

Give 6 reasons for reduced variability in foetal HR

Answer 21

1. Foetal sleeping - this is the most common cause but will not last for any more than 40 minutes
2. Foetal acidosis - due to hypoxia (more likely if there are also late decelerations)
3. Foetal tachycardia
4. Drugs - opiates, benzodiazepines, methyldopa and magnesium sulphate
5. Prematurity - <28 weeks
6. Congenital heart abnormalities

Question 22

When should accelerations be seen if the foetus is healthy?

Answer 22

At the same time as uterine contractions

Question 23

What causes an early deceleration?

Answer 23

This is due to increased foetal intracranial pressure and this increases vagal tone. Once the contraction ends and the foetal intracranial pressure returns to normal, the deceleration ends. This means this is a physiological deceleration.