Fetal Monitoring

Question 1

What is the correct baseline rate of a foetal tachycardia? What are the causes?

Answer 1

160bpm
Foetal hypoxia
Chorioamnionitis – if maternal fever also present
Hyperthyroidism
Foetal or maternal anaemia
Foetal tachyarrhythmia

Question 2

What is the definition of a prolonged deceleration on CTG?

Answer 2

Deceleration that lasts more than 2 minutes

Prolonged deceleration/bradycardia: Baseline <90bpm indicates impending demise- ACT!

Question 3

What is common method used to monitor a foetus in utero?

Answer 3

CTG (not usually done before 26weeks)

Confidently used after 32weeks

Question 4

What do the different lines (from top to bottom) correspond to?

Answer 4

1: Fetal heart beat
2: Mother presses for fatal movement
3: Actual fetal movement
4: Contraction

Question 5

What is a CTG acceleration defined as?

Answer 5

Rise of >15bpm for 15secs

Question 6

What is a CTG deceleration defined as?

Answer 6

Drop of >15bpm for 15secs

Question 7

What is the number of normal variability?

Answer 7

5bpm

Find a squiggly bit on the fetal HR and measure the distance between the peak & trough

Question 8

What are the normal rate of contractions during labour?

Answer 8

4-5/ 10mins

Question 9

What is a normal fetal heart rate?

Answer 9

100-160bpm

Question 10

What does the contractions line on a CTG show?

Answer 10

Frequency & duration

NOT intensity

Question 11

Is the absence of accelerations a bad thing?

Answer 11

Not necessarily

Babies in utero sleep

Question 12

What are the types of decelerations?

Answer 12

Early: Occur with the beginning of a contraction and normalise by the end of the contraction
Late: Occur with the end of a contraction and normalise after the contraction
Early & Late: Uniform in shape, depth & length
Variable: typical (vary in shape & timing related to contraction) & atypical

Question 13

How are early & late decelerations defined?

Answer 13

E: HR dip always before uterine contraction peak
L: HR dip always after uterine contraction peak

Question 14

What can be done with a worrying CTG?

Answer 14

• Change to maternal left lateral position
• Give fluids (dehydrated)
• Fetal scalp stimulation
• Fetal blood sample
• Delivery

Question 15

When should a fatal blood sample be taken?

Answer 15

Worried about CTG but delivery not imminent
At least 3cm dilated
Measurement of fetal pH

Question 16

What are the different parameters you should cover on a CTG?

Answer 16

DR C BRAVADO
Determine risk
Contractions
Baseline
Variability
Accelerations
Decelerations
Overall impression (normal, reassuring, abnormal)

Question 17

What are the indications for CTG monitoring?

Answer 17

Maternal: Pain, pre-eclampsia, DM, APH
Fetal: IUGR, Prematurity, oligohydramnios, multiple, breech
Intrapartum: IOL, Oxytocin infusion

Question 18

What can cause sustained tachycardia on a CTG?

Answer 18

Prematurity
Hypoxia
Fetal distress
Maternal pyrexia
Exogenous beta agonist use (Salbutamol)

Question 19

What might baseline bradycardia on a CTG suggest?

Answer 19

Severe fetal distress

?Due to: Abruption, uterine rupture, hypotension, maternal sedation, hypoxia, postmaturity

Question 20

When can reduced variability be commonly seen?

Answer 20

Fetal sleep cycles
Safely last up to 40mins
>90mins = abnormal
Drugs: Opiates, benzos

Question 21

Is prolonged reduced variability okay?

Answer 21

Sign of acute fetal distress!

Question 22

What are the causes of typical variable decelerations?

Answer 22

Cord compression especially in oligohydramnios

Question 23

What is shouldering?

Answer 23

Sign fetus is comping well with compression
Small acceleration before & after a deceleration

If present >50% of contractions for >90mins become non-reassuring

Question 24

What are the different managements for each result of a fetal blood sample?

Answer 24

Normal: pH >7.25= labour continues
Borderline: pH 7.20-7.25= Repeat pH needed in 30-60mins
Abnormal: pH <7.20= fetal compromise- DELIVER

Question 25

What is a sinusoidal trace?

Answer 25

Smooth undulating sine wave
No variability
Patterns lasts >10mins
Amplitude 5-15bpm
Cause: Physiological or fetal anaemia, hypoxia
Serious until proven otherwise