Foetal monitoring Flashcards
How would you monitor the foetus of a low risk mother?
Intermittent auscultation (sonicaid/doppler)
monitor baby’s heart rate after every contraction (if mother is low risk)
How would you monitor the foetus of a high-risk mother in labour?
Continuous monitoring eg. CTG cardiotocograph
Bottom probe picks up heart rate (top trace)
Top probe picks up contractions (bottom trace)
Every time a woman feel foetal movement, presses a button
What are some examples of high-risk situations in which you might use CTG cartiotocography?
Any pregnancy which is not low risk eg.
Oxytocin infusion
Meconium stained liquor
Multiple pregnancy
Intra-uterine growth restriction (IUGR)
Abnormality on intermittent auscultation
When might you use a foetal scalp electrode over an abdominal transducer?
Poor contact with abdo transducer
High BMI
Twins (can’t decipher between babies)
Baby is too active
Abdo scarring (sound waves don’t go through very well)
What is the baseline foetal heart rate?
100-160 bpm
What is an acceleration - is that a good or a bad thing?
Rise of >15bpm for 15 seconds
good - indicates movement
What is a deceleration - is this a good or a bad thing?
drop of >15bpm for 15 seconds
bad (if late). Not concerning if early
What are the benefits of CTG?
reduced rate of neonatal seizures
increases intervention rate
What are the limits/drawbacks of CTG?
No clear benefit of cerebral palsy and perinatal death
What should you do if you are worried about a CTG?
Change maternal position (to left lateral)
Give fluids - ?dehydrated (less perfusion to baby)
Fetal scalp stimulation
Foetal blood sample (if concerned and delivery is not imminent)
Deliver
How many centimetres dilated must someone be before foetal blood sample can be taken?
3cm
Why are foetal blood samples useful?
Immediate and accurate result re. baby’s welfare
Measures foetal pH (indicative of hypoxaemia)
What doe foetal blood samples measure?
Foetal pH (indicative of hypoxaemia)
What does a foetal pH of >7.25 indicate?
normal - baby is not hypoxaemic
What does a foetal pH of 7.20-7.25 indicate?
borderline ?hypxoaemic
What does a foetal pH <7.20 indicate that you should do?
DELIVER
What is the mnemonic for interpreting CTGs?
DR C BRAVADO
DR: determine risk - why is woman on CTG?
C: contractions
BR: baseline rate
A: accelerations
VA: variability
D: decelerations
O: Overall impression eg. normal/reassuring, non-reassuring/abnormal
What should happen to the baby’s heart rate when it moves in the womb?
HR should increase (acceleration)
How are contractions classified?
per 10 minutes
How do contractions present on CTG?
Peaks
What is the desired rate of contractions on a CTG during labour?
4-5:10
How do you measure the intensity of contractions?
Mother will tell you
palpate
Why is a flat trace a concern in a CTG?
shows no variability (therefore shows damage to PONS and lack of sympathetic/parasympathetic competition)
What is the ideal variability on a CTG?
> 5bpm or more
What do accelerations show?
Foetal movement
What is a deceleration on a CTG?
> 15 beats for >15 seconds
What can decelerations indicate?
placental insufficiency
When do LATE decelerations occur?
have to occur after contraction
BUT
HAVE TO ALL BE EXACTLY THE SAME TIME AFTERWARDS TO BE CLASSED AS LATE
What is a typical variable deceleration?
deceleration of <60 beats for <60 seconds
What is an atypical variable deceleration?
deceleration of >60 beats for >60 seconds (profound and broad drops)
What is the problem with the false-positive rate in CTG?
can mean that some interventions occur unnecessarily and can cause distress for a mother that was otherwise not needed
Why is Left lateral position the best position for a mother?
takes pressure of IVC, therefore allows better blood supply to baby
What is a more accurate test of baby’s hypoxia level than a CTG?
Foetal blood sample
What can cause an increase in heart rate in a baby? (other than foetal movements)
foetal distress
infection
maternal dehydration (less blood volume going to baby)
How can an epidural effect foetal heart rate?
What should you do about this?
tachycardia/bradycardia - any changes to CTG
because:
Maternal BP drops
Less blood to baby
baby becomes distressed
First thing to do: Left lateral position
1L of fluids STAT.
What foetal heart rate is needed to maintain cerebral perfusion?
100 for 50% of time
