Fetal monitoring

Question 1

What does the umbilical vein carry?

Answer 1

Oxygenated, nutrient-rich blood from the placenta to the fetus, and the umbilical arteries carry deoxygenated, nutrient- depleted blood from the fetus to the placenta.

Question 2

What other tools are used for monitoring fetal wellbeing in the NICE guidelines 2022?

Answer 2

Perform and document a systematic assessment of the condition of the woman and unborn baby every hour, or more frequently if there are concerns.
 Take into account other factors including birthing persons reports of frequency, length and strength of contractions.
 Antenatal and intrapartum risk factors for fetal compromise.
 Current wellbeing of the birthing person and unborn baby.
 How labour is progressing.
 Include birthing companion in these discussions.
 Intermittent and continuous monitoring.
 Eyes, ears, communication, skills and expertise.
 Building a clinical picture

Question 3

What should you do if fetal heart rate concerns are confirmed (NICE 22)

Answer 3

Summon help
Advise continuous CTG monitoring and explain why this is recommended and the implications for the choices and place of care.
Transfer from midwifery led care to obstetric led care

Question 4

When is continuous CTG monitoring advised?

Answer 4

If fetal heart concerns arise with intermittent auscultation and are ongoing, or intrapartum maternal or fetal risk factors develop

Question 5

What anternatal maternal risk factored are offered a continuous CTG whilst in labour?

Answer 5

Previous caesarean birth or other full thickness uterine scar
Hypertensive disorder needing medication
PROM and any other vaginal blood loss other than a show
Suspected chorioamnionitis or maternal sepsis
Pre assisting diabetes and gestational requiring medications
Non-cephalic presentation
FGR
Advanced gestational age (<42)
Anhydraminos or polyhydraminous
Reduced FM

Question 6

What are the 4 key elements do saving babies lives aim to do to reduce stillbirth and early neonatal death

Answer 6

1) Reducing cigarette smoking in pregnancy
2) Improving detection and management of FGR
3)Improving awareness and management of RFM
4) Promoting effective fetal monitoring during labour.

Question 7

What is the aim of saving babies lives?

Answer 7

A programme aimed at improving outcomes by improving quality of care during pregnancy and outcomes through 4 key elements.

Question 8

What is Fresh eyes?

Answer 8

A buddy system should be sued to help provide an objective holistic review. This should be undertaken at least hourly when CTG monitoring is used and at least 4 hourly when IA is utilised, unless there is a trigger to provide holisti review earlier.

Question 9

What are the things to look for in CTG interpretations by Marshall and Raynor 2020?

Answer 9

Categorised by systematically analysing 4 features of the FHR.
Baseline heartrate
Baseline variability
Decelerations
Accelerations
Reassuring, non-reassuring or abnormal-in context of uterine activity
Overall classification: normal, suspicious or pathological

Question 10

According to NICE 2022, when reviewing a CG trace what should you assess and document?

Answer 10

Contractions
Baseline FHR
Variability
Presence or absence of decelerations (and characteristics of declerations if present)
Presence of accelerations

Question 11

What is a normal CTG characterized as according to NICE 2022?

Answer 11

If there is a stable baseline fetal heart rate between 110 and 160 beats a minute and normal variability, continue usual care as the risk of fetal acidosis is low.

Question 12

What are contractions recorded as on a CTG?

Answer 12

Bell-shaped gradual increases in the uterine activity signal followed by roughly symmetrical decreases.

Question 13

What should you do if the frequency of contractions cannot be assessed reliably by the toco?

Answer 13

manual palpation for 10 minutes every 30 minutes is required. The intensity and duration of contractions may be assessed by manual palpation.

Question 14

what may happen if contractions become too frequent or last too long and why?

Answer 14

Baby will begin to decompensate because there is an interruption to the baby’s oxygen supply with each contraction

Question 15

What is tachysystole?

Answer 15

Excessive frequency of contractions, defined as the occurrence of more than 5 contractions in 10 minutes, in two successive 10 minute periods or average over a 30 min period.

Question 16

What is meant by hyperstimulation?

Answer 16

Exaggerated response to uterine stimulants, presenting as an increase in frequency of the contractions, strength of uterine contraction, increased uterine tone between contractions and/ore prolonged contractions for over 2 hours (hypertonus)

Question 17

What may hyperstimualtion lead to?

Answer 17

To fetal heart rate changes

Question 18

What is meant by the baseline FHR?

Answer 18

The mean FHR visible on the CTG rounded to increments of 5bpm in 10 min segments.
The baseline must be for a min of 2 minutes in a ten minute segment .
Otherwise the baseline fir the segment is described as indeterminate.

Question 19

What is a normal baseline(NICE 22) and what is it important to consider?

Answer 19

A value between 110 and 160bpm.
It is important to review previous FHR traces and consider the current gestational age when assessing if the baseline really is normal for this baby.

Question 20

What are the differences in baseline rates for pre term and post term fetuses and why?

Answer 20

Preterm fetuses tend to have values towards the upper end of ‘normal’
Posterm fetuses tend to have values towards the lower end of ‘normal’
This is due to the development of the NS as development progresses.

Question 21

What are baseline rate and variability determined by?

Answer 21

Fluctuation and balance in the ANS between the sympathetic and parasympathetic systems.

Question 22

What is meant by the sympathetic system?

Answer 22

Best known for its role in responding to dangerous or stressful situations. In these situations, your sympathetic nervous system activates to speed up your heart rate, deliver more blood to areas of your body that need more oxygen or other responses to help your get out of danger

Question 23

What is meant by the parasympathtic system?

Answer 23

Responsible for the body’s rest and digestion response when the body is relaxed and resting. It undoes the work of sympathetic division after a stressful situation.

Question 24

Why is the stability of baseline important?

Answer 24

An unstable or gradually rising baseline could be an indication that the baby’s NS and therefore brain are not functioning as they should be

Question 25

Is there such thing as an uncomplicated tachycardia?

Answer 25

There are many causes for a fetal tachycardia (above 160bpm), some are reversible and due to maternal condition e.g. maternal tachycardia or pyrexia, and some may be a response to fetal hypoxia or infection. Recognition of fetal tachycardia, the suspected cause and how to manage the situation is paramount. When there is a reason for fetal tachycardia, it can have an impact on fetal wellbeing if not rectified due to reduced resting phase of the myocardium and therefore reduced oxygenation

Question 26

Should we be worried if there is baseline bradychardia?

Answer 26

This is defined as a baseline value below 110 bpm lasting more than 10 minutes. Values between 90 and 110 bpm may occur in a normal fetus, especially in a postdates pregnancy. You will find that the m/w will take steps to confirm that this is not the maternal heartbeat and that the trace shows a stable baseline and normal baseline variability. A senior obstetric review will be required before classifying the trace as normal.

Question 27

What is meant by variability?

Answer 27

This refers to the variation in the FHR above and below the baseline, evaluated as the average bandwidth amplitude of the signal in 1 minute segments.
The fluctuations should be irregular in amplitude and frequency
Variability is documented in BPM

Question 28

What is a Normal variability?

Answer 28

A bandwidth amplitude of 5-25bpm

Question 29

What is an increased variability?

Answer 29

A bandwidth amplitude of >25bpm

Question 30

What is a reduced variability?

Answer 30

A bandwidth amplitude below 5bpm

Question 31

What is an absent variability?

Answer 31

Amplitude range undetectable with or without fetal decelerations.

Question 32

What does variability represent?

Answer 32

Fluctuation in FHR. Fetal activity. Fetal energy

Question 33

What is meant by increased variability and what may this be associated with?

Answer 33

exceeding 25bpm for over 30mins pathophysiology not completely understood. Nay be associated with hyperactivity due to recurrent decelerations.

Question 34

What is meant by decreased variability and what may this indicate?

Answer 34

For over 50 mins indicative CNS hypoxia- should be escalated for review.

Question 35

Why is the NS highly vulnerable during labour?

Answer 35

vulnerable to injuries due to hypoxia, energy deprivation or oxidative stress.

Question 36

What is meant by a sinusoidal pattern?

Answer 36

Sinusoidal pattern presents as a regular, smooth, undulating signal, resembling a wave, with an amplitude of 5−15 bpm, and a frequency of 3−5 cycles per minute.
This pattern lasts more than 30 minutes and coincides with absent accelerations.
The pathophysiological basis of the sinusoidal pattern isn’t completely understood, but it occurs in association with severe fetal anaemia. It has also been described in cases of acute fetal hypoxia, infection, cardiac malformations, hydrocephalus, and gastroschisis.

Question 37

What is meant by a pseudo sinusoidal pattern?

Answer 37

A pattern resembling the sinusoidal pattern, but with a more jagged “saw-tooth” or “sharktooth” appearance, rather than the smooth wave form.
Its duration seldom exceeds 30 minutes, and it is characterized by normal fetal heart patterns before and after. Accelerations may also be present in a pseudo sinusoidal trace.
This pattern has been described after analgesic administration to the mother, and during periods of fetal sucking and other mouth movements

Question 38

What is meant by accelerations?

Answer 38

These are abrupt increases in FHR above the baseline, of more than 15bpm in amplitude, and lasting more than 15 seconds but less than 10 minutes.
An acceleration must start from and return to a stable baseline.

Question 39

When may accelerations occur less or more frequently?

Answer 39

More: In the active fetal behavioural state, they often accompany fetal movements and occur in relation to the level or central nervous system activity.
Less: Before 32 weeks of gestation, amplitude and duration of acceleration may be lower.

Question 40

What is meant by decelerations?

Answer 40

These are defined as decreases in the FHR below the baseline of more than 15bpm and lasting more than 15 seconds.
HOWEVER
attention should always be paid to ‘shallow decelerations’ in the presence of a rising/raised baseline and/ore reduced variability.

Question 41

What are early decelerations?

Answer 41

• Rare (<5% of decelerations)
• Uniform in size, shape and duration
• Generally only seen in the late first or second stage of labour
• Commonly due to head compression or vagal stimulation and thus are not generally considered to indicate hypoxia.

Question 42

What are late decelerations?

Answer 42

Account for around 5%of decelerations
*Commence after a contraction starts and end after the contraction has ended
* Must be uniform in both length and depth; for this reason true late decelerations are uncommon.

Question 43

What are late decelerations a feature of?

Answer 43

uteroplacental insufficiency and are never considered normal.

Question 44

What is meant by prolonged decelerations?

Answer 44

Reductions in FHR greater than 15bpm from baseline and lasting for more than 3 minutes. Acute hypoxia most commonly presents with a prolonged deceleration on the CTG.

Question 45

What are some conditions that can be caused from prolonged decelerations?

Answer 45

cord prolapse, scar dehiscence, major placental abruption and uterine hyperstimualtion, maternal hypotension…

Question 46

What is meant by variable decelerations?

Answer 46

Variable decelerations account for the majority(>90%) of decelerations
seen in established labour. Variable decelerations vary in size, shape and timing with respect to one
another and uterine contractions. Variable decelerations are usually due to umbilical cord compression

Question 47

What are some characteristics of variable decelerations?

Answer 47

-lasting more than 60 seconds
-reduced variability within deceleration
-failure to return to baseline
-bisphasic (w) shape
-no shouldering
-shouldering vs overshooting

Question 48

what is the physiology of shouldering?

Answer 48

 The cord consists of 2 arteries & 1 vein.
 Occlusion of the narrow-walled vein occurs first during a uterine contraction causing a transient rise in the heart rate resulting in the anterior shoulder.
 Further cord compression & occlusion of the arteries cause a rapid increase in fetal blood pressure and stimulate a vagal response which gives the deceleration in the heart rate.
 Once compression is released, the elastic arteries bounce open causing a transient rise in the heart rate resulting in the posterior shoulder. Heart rate returns to baseline as blood pressure normalises.

Question 49

What are overshoots caused by?

Answer 49

Due to a rebound increase in heart rate caused by brief accumulation of CO2 during hypoxic episodes.

Question 50

What is the characterisation of the behavioural cycle: active sleep (rapid eye movements)?

Answer 50

This is the most frequent behavioural state and is represented by a moderate number of accelerations and normal variability.

Question 51

What is the characterisation of the behavioural cycle: Wakefulness

Answer 51

Active wakefulness is rarer and represented by a large number of accelerations and normal variability. In this pattern, accelerations may be so frequent as to cause difficulties in baseline estimation.

Question 52

What is the characterisation of the behavioural cycle: fetal quiescence/ sleep

Answer 52

reflecting deep sleep (no eye movements):Deep sleep can last up to 40- 50minutes and is associated with astable baseline, very rare accelerations, and borderline variability

Question 53

What is it meant when a CTG alternates between these different behavioural states?

Answer 53

cycling

Question 54

What could the behavioural state: cycling mean?

Answer 54

It is a hallmark of fetal neurological responsiveness and absence of hypoxia/acidosis.

Question 55

What are the 4 types of hypoxia?

Answer 55

Gradually evolving
acute
subacute
chronic

Question 56

What is the fetal response to acute hypoxia?

Answer 56

 Prolonged deceleration of less than 80bpm lasting 3+ minutes. Cord prolapse/abruption/uterine rupture.
 Iatrogenic causes – hypotension.
 When FH drops – significant reduction in CO2 expulsion leading to respiratory acidosis.
 If continued, due to reduced O2 intake – anaerobic metabolism occurs and metabolic acidosis (build-up of acid in body) = low pH, fetal distress, poor APGAR.
 pH ranges - Normal: 7.25 or above. Borderline: 7.21 to 7.24.
 Fetal pH can fall at a rate of 0.01/m.
 A pH of 7.25 can fall to 7.15 in 10 minutes
 A fetal scalp blood pH level of less than 7.20 is considered abnormal. In general, low pH suggests that the baby does not have enough oxygen

Question 57

What is the fetal response to sub-acute hypoxia?

Answer 57

Presents on the CTG by the fetus spending most of the time in decelerations
This is almost invariably caused by uterine hyperstimualtion. Although is may also be seen in the active stage of labour.
Fetal PH drops at a rate of 0.01/2-3 minutes.

Question 58

What is the fetal response to chronic hypoxia?

Answer 58

Presents as a baseline rate at the upper end of normal associated with reduced variability and blunted responses (infrequent accelerations and lack of cycling) and is frequently associated with shallow decelerations.

Question 59

What does chronic hypoxia represent in a fetus?

Answer 59

represents a fetus with reduced reserve and increased susceptibility to hypxic injury during labour.