CTG Monitoring

Question 1

What do the following abbreviations stand for in CTG monitoring?

DR
C
BRa
V
A
D
O

Answer 1

Define Risk
Contractions
Baseline Rate
Variability
Accelerations
Decelerations
Overall impression

Question 2

What is define risk?

Answer 2

Defining whether a pregnancy is high or low risk. It gives you context to the CTG and may change your threshold for intervention

Question 3

What do you need to record about contractions?

Answer 3

Number in a 10 minute period (seen as peaks of uterine activity on CTG)

Strength and duration

Question 4

What is a normal fetal heart rate?

Answer 4

110-160

Question 5

How is a baseline fetal heart rate calculated?

Answer 5

Average in 10 minute window

Ignore accelerations and decelerations

Question 6

How is prolonged severe bradycardia in a fetus defined?

Answer 6

<80bpm for >3 mins

Question 7

What conditions are associated with fetal tachycardia?

Answer 7

Fetal hypoxia
Chorioamnionitis
Maternal or fetal anaemia
Hyperthyroidism

Question 8

What conditions are associated with fetal bradycardia?

Answer 8

Prolonged gestation
Transverse or posterior occiput presentation

(100-120 bpm)

Question 9

What conditions are associated with prolonged severe fetal bradycardia?

Answer 9

Prolonged cord compression
Cord prolapse
Epidural
Rapid fetal descent

Question 10

What does baseline variability on a CTG tell you? What is a normal variability?

Answer 10

How a fetus’ HR varies from one beat to the next

Indicate fetus is adapting to environment due to input from nervous system, baroreceptors and chemoreceptors

Normal is 5-25

Question 11

What could cause reduced fetal variability?

Answer 11

Fetus sleeping
Fetal acidosis - hypoxia
Fetal tachycardia
Congenital heart defect
Prematurity
Maternal medication - opiates, benzo, methyldopa, magnesium sulphate

Question 12

What is a fetal acceleration?

Answer 12

Abrupt increase in baseline fetal HR

> 15bpm for >15s

They are reassuring

Question 13

What is a fetal deceleration?

Answer 13

Abrupt decrease in baseline fetal HR of >15bpm for >15s

Question 14

Why do foetuses reduce their heart rate?

Answer 14

In response to hypoxia to reduce myocardial demand and preserve myocardial oxygenation and perfusion

Fetus can’t change respiratory depth or rate

Question 15

What is an early deceleration?

Answer 15

Start when uterus contract and recover when contraction stop

Due to fetal RICP and increasing vagal tone

Physiological deceleration

Question 16

What is a variable deceleration?

Answer 16

Rapid fall in heart rate with variable recovery phase

May not have any relationship to contractions

Seen in labour and with oligohydramnios patients

Question 17

What are “shoulders of decelerations”?

Answer 17

Accelerations occur before and after deceleration

Indicate fetus still able to adapt and not yet hypoxic

Question 18

What causes the acceleration, deceleration, acceleration in shoulders of decelerations?

Answer 18

Umbilical vein occluded - acceleration

Umbilical artery occluded - deceleration

Pressure off cord - acceleration

Question 19

What is a late deceleration?

Answer 19

Begin at peak of contraction and recover after it has ended

Indicate lack of blood supply to uterus and placenta - hypoxia and acidosis

Question 20

What causes late decelerations?

Answer 20

Maternal hypotension
Pre-eclampsia
Uterine hyperstimulation

Question 21

What must you do if you see a late deceleration?

Answer 21

Fetal blood sampling for pH

Question 22

What is a prolonged deceleration?

Answer 22

Deceleration lasting >3mins

Fetal blood sampling or emergency C section needs to be arranged

Question 23

What is a sinusoidal pattern on a CTG?

Answer 23

Smooth regular wave like pattern with no beat to beat variability

Question 24

What can cause a sinusoidal CTG pattern?

Answer 24

Severe fetal hypoxia
Severe fetal anaemia
Haemorrhage

Very concerning and associated with high levels of morbidity and mortality

Question 25

What would be seen on a reassuring CTG?

Answer 25

110-160bpm 5-25 variability No or early decelerations Variable decelerations with no concerning characteristics <90 mins

Question 26

What characteristics of variable decelerations are concerning?

Answer 26

``` >60s Reduced baseline variability within deceleration Fail to return to baseline Biphasic (W) shape No Shouldering ```

Question 27

What features of a CTG would be considered non-reassuring?

Answer 27

100-109bpm OR 160-181bpm Variability <5 for 30-50mins or >25 for 15-25mins Variable decelerations with no concerns >90mins Variable decelerations with concerns in <50% of contractions >30mins Variable decelerations with concerns in >50% of contractions <30mins Late in >50% of contractions for <30 mins with no clinical risk factors (bleeding or meconium)

Question 28

What features of a CTG would be considered abnormal?

Answer 28

<100 or >180 bpm Variability <5 for >50 mins OR >25 for >25mins OR sinusoidal pattern Variable decelerations with concerns >50% of contractions for >30 mins Late decelerations >30mins Acute bradycardia Single prolonged deceleration >3mins

Question 29

What is a normal CTG and what is the management?

Answer 29

All features reassuring Continue CTG and usual care

Question 30

What is a suspicious CTG and how is it managed?

Answer 30

1 non-reassuring AND 2 reassuring features Seek advice from obstetrician or senior midwife, correct underlying causes, full set of maternal obs

Question 31

What is a pathological CTG?

Answer 31

1 abnormal feature OR 2 non reassuring features

Question 32

How is a pathological CTG managed?

Answer 32

Seek advice - obstetrician or senior midwife Correct underlying cause Exclude acute events - cord prolapse, placental abruption, uterine rupture Offer digital fetal scalp stimulation If still pathological after scalp stimulation, consider fetal blood sample and expediting birth

Question 33

What CTG requires urgent intervention?

Answer 33

Acute bradycardia | Single prolonged deceleration >3mins

Question 34

What is done if a CTG requires urgent intervention

Answer 34

``` Urgently seek obstetrician help Correct underlying causes Expedite birth if acute event Prepare for urgent birth Expedite birth if bradycardia >9mins Discuss expedited birth if bradycardia recover ```

Question 35

What are the CI's for fetal blood sampling?

Answer 35

Risk of maternal-fatal infection | Fetal bleeding disorders

Question 36

What results are in a normal fetal blood sample? What is the next step?

Answer 36

Lactate <=4.1mmol/L pH >= 7.25 Repeat in an hour

Question 37

What results are in a Borderline fetal blood sample? What is the next step?

Answer 37

Lactate 4.2-4.8mmol/L pH 7.21-7.24 Repeat in 30 mins

Question 38

What results are in a Abnormal fetal blood sample? What is the next step?

Answer 38

Lactate >=4.9 mmol/L pH <=7.20 Expedite birth