CTG

Question 1

basic way that a CTG works

Answer 1

ultrasound doppler measures foetal HR

at the same time, ultrasound checks for the tension of the uterine wall (i.e. contraction)

Question 2

8 indications for CTG

Answer 2

sepsis

maternal tachycardia >120

disproportionate maternal pain

significant meconium

pre-eclampsia

fresh antepartum haemorrhage

delay in labour

use of oxytocin

Question 3

are foetal accelerations normal?

Answer 3

yes - especially when they occur alongside the contractions

Question 4

foetal heart rate:

normal

non-reassuring

Answer 4

110-160

<110 OR >160

Question 5

FOETAL HEART RATE VARIABILITY

normal

non-reassuring (2)

abnormal (2)

Answer 5

5-25

<5 for 30-50 minutes or >25 for 15-25 minutes

<5 for >50 minutes or >25 for >25 minutes

Question 6

what are early decelerations and what causes them?

Answer 6

the nadir of the deceleration corresponds to the peak of the contraction

they are caused by compression of the foetal head and therefore vagal nerve stimulation

Question 7

what are late decelerations and what causes them?

Answer 7

the nadir of the deceleration occurs after the peak of the contraction

these indicate foetal hypoxia

Question 8

what are variable decelerations and what causes them?

Answer 8

brief decelerations of more than 15 bpm for less than 2 minutes, with the nadir reached within 30 seconds of the deceleration occurring

caused by intermittent compression of the umbilical cord

Question 9

in the context of CTG, what are “shoulders”?

what do they indicate?

Answer 9

brief accelerations before and after a variable deceleration; these indicate that the baby is coping well with the transient hypoxia

Question 10

what are prolonged decelerations?

what do they indicate?

Answer 10

decelerations >15bpm lasting longer than 2 minutes but less than 10 minutes

this indicates prolonged hypoxia and is a concerning/abnormal sign

Question 11

when are variable decelerations classified as reassuring?

Answer 11

when they occur for <90 minutes and do not have concerning features

Question 12

which type of decelerations are always abnormal?

Answer 12

prolonged

Question 13

how concerning are late decelerations?

Answer 13

they are “non-reassuring”

Question 14

4 categories of CTG

Answer 14

normal

suspicious: a single non-reassuring feature
pathological: two non-reassuring or one abnormal

Need for urgent intervention: acute bradycardia or prolonged decelerations for >3 minutes`

Question 15

what does foetal scalp stimulation hope to acheive?

Answer 15

it is a means of assessing if the foetus is responsive to stimuli

an acceleration is reassuring

Question 16

maternal factors which can cause foetal hypoxia

Answer 16

maternal hypoxia

maternal hypotension

Question 17

rule of 3 with foetal bradycardia

Answer 17

3 minutes = call for help

6 minutes = move to theatre

9 minutes = prepare for delivery

12 minutes = deliver the baby (within the next 3 minutes)

Question 18

what does a sinusoidal CTG indicate?

Answer 18

severe foetal compromise, most commonly due to anaemia from e.g. vasa praevia