Abnormal labour and CTG assessment Flashcards
What consistutes an abnormal labour ?
- Too early - preterm birth
- Too late - induction of labour
- Too painful - requires anaesthetic input
- Too long - failure to progress
- Fetal distress - hypoxia/sepsis
- Requires intervention - operative birth
What is done to assess progress in labour ?
Checking:
- Cervical dilatation
- Descent of presenting part
- Signs of obstruction
When describing descent of the presenting part how is it done ?
It is done by describing it in relation to the ischial spines (palpate them) with numbers -5 to +5
For instrumental delivery if necessary, what level should the presenting part be at?
At least the level of the ischial spines or lower
When in the active phase of stage 1 of labour is it considered to be prolonged/delayed
- In Nulliparous women when there is <2cm dilation in 4 hours
- In Parous women when there is <2cm dilation in 4 hours or slowing in progress
When is it considered prolonged/delayed in stage 2 of labour ?
- In nulliparous women it is considered prolonged if it exceeds 3hrs with regional anaesthesia or 2hrs without
- In multiparous women it is considered prolonged if it exceeds 2hrs with regional anaesthesia or 1hr without
Referring to the 3P’s involved in labour what problems in-realtion to each of them can result in failure to progress?
- POWER - inadequate contractions, either the freqeuncy &/or the strength of them
- PASSAGES - short stature/considerable trauma to pelvis/shape of the pelvis
- PASSANGER - big baby, malposition of head (remember babies head moves in relation to match widest dimensions of pelvis with the widest part of the head)
Go over the diameters of the pelvis
- Pelvic Inlet - Transverse diameter 13.5cm / AP diameter 11cm
- Mid-cavity - Transverse diameter 12cm / AP diameter 12cm
- Pelvic Outlet - Transverse diameter 11cm / AP diameter 13.5cm
Go over the diameters of the babies head
What is the commonest reason why a baby doesn’t progress?
- The position of the head
- Attidue meaning (flexed or extended)
Describe the descent of the baby during labour
- As the fetal head engages and descends it assumes an occipitut transverse position because transverse diameter of the pelvis inlet is the widest part
- Whilst descending the fetal head flexes so that chin is touching chest, the fetal position remains occiput transverese. When the head flexes the pos. fontanelle is now at the centre of the birth canal and the ant. fontanelle is more moreate & difficult to find
- Internal rotation: fruther descent, the occiput (back of head) rotates anterioly & fetal head assumes an oblique orientation or may rotate completely to occiput ant. position
- Extension: curve of the sacrum causes extension of the head as it descends further
- External rotation: shoulders rotate into an oblique position or ant.post. position (baby sleeping on side again) with this fetus head returns to transverse-occiput position this return to original position is known as restitution
When is a partogram used ?
It is commenced as soon as a women enters labour ward & is a sheat like a NEWS score chart
What does a program record & measure ?
- Fetal Heart
- Amniotic Fluid - meconium staining is not a good sign
- Cervical Dilatation
- Descent
- Contractions
- Obstruction - Moulding
- Maternal Observations
What should you do ?
- Get her moving about, give her food
- Try oxytocin
What should you do ?
- She is small and this baby is big
- She needs a C-section
- If not – she could get uterine rupture – due to oxytocins on a person who has had a baby before.
What monitoring is required during labour ?
- Doppler ascultation of fetal HR: During stage 1 - during or after a contraction every 15 mins for at least 1min. During stage 2 - every 5-10mins for at least 1min (or continuously via CTG if women has risk factors)
- Contractions assessed every 30min
- Maternal pulse rate assessed every 60min
- Maternal BP and temp should be checked every 4 hours
- VE should be offered every 4 hours to check progression of labour
- Maternal urine should be checked for ketones and protein every 4 hours
What are the risk factors for fetal hypoxia during labour and therefore what is done ?
- Small fetus
- Preterm / Post Dates
- Antepartum haemorrhage
- Hypertension / Pre-eclampsia
- Diabetes
- Meconium
- Epidural analgesia
- Previous c-section but having a vaginal birth now (VBAC)
- PROM >24h
- Sepsis (Temp > 38C)
- Induction / Augmentation of labour
►therefore CTG monitoring done
List the potential underlying causes of fetal distress during labour
Acute causes:
- Abruption
- Vasa Praevia
- Cord Prolapse
- Uterine Rupture
- Feto-maternal Haemorrhage
- Uterine Hyperstimulation
- Regional Anaesthesia
Subacute:
- Hypoxia
What can be an early sign of fetal distress and what does it signify ?
Passage of meconium in labour is a sign of fetal distress and may signift fetal hypoxia
What is fetal hypoxia indicated by ?
- Tachycardia >160
- Loss of variability in fetal HR CTG baseline
- Irregularity in fetal HR (esp deccelarations)
- Acute bradycardia or a single prolonged deceleration lasting longer than 3mins
If fetal HR falls < 100 what is urgently required ?
Urgent assessment with fetal blood sampling may be done to confirm hypoxia.
When significant hypoxia is shown to be present in fetus what should be done ?
prompt delivery by the quickest method i.e. c-section or vaginal extraction
What does prolonged or repeated hypoxia in the fetus result in ?
Acidosis
What is the mnemonic for remembering how to interpret a CTG ?
- DR - define risk
- C - contractions
- BRa - Baseline rate
- V - variability
- A - accelerations
- D - deccelerations
- O - overall impression
DR C BRAVADO
What should be considered when defining risk (DR) when looking at a CTG?
Define the pregnancy as high or low risk (refer abck to risk factors listed for fetal hypoxia)
When assessing the contractions on a CTG what do you need to know?
- The number of contractions in 10mins (each big square = 1 min, count from peak of one contraction to the next)
- Assess duration of contractions
- Assess intensity of contractions using palpation
How do you assess the BRa (baseline rate) on a CTG
- This is the average HR within a 10min window
- Look at the CTG & assess the average HR in the last 10mins, ignoring accelerations and deccelerations
- Normal is 110-160
- Non-reassuring = 100-109 or 161-180
- Abnormal = <100 or >180
What are the causes of fetal tachycardia ?
- Hypoxia
- Chorioammionitis
- Hyperthyroidism
- Fetal or maternal anaemia
- Fetal tachyarrhythmia
List causes of mild (100-120) fetal bradycardia
- Post-dates gestation (norm for baby HR to decrease as it gets older)
- Occiput post. or transverse presentation
Severe prolonged bradycardia (<80) for > 3mins indicates hypoxia, what are the causes ?
- Prolonged cord compression
- Cord prolapse
- Epidural & spinal anaesthesia
- Maternal seizures
- Rapid fetal descent
What is variability on CTG
- Variability refers to the variation of the fetal HR
- It occurs due to interaction between the nervous system, chemoreceptors, baroreceptors & cardiac responsiveness ==> it is a good indicator of how healthy a fetus is as a health fetus will constantly be adapting its HR in response to its environment
How is variability on CTG calculated and what are the 3 categories of it
It is calculated by looking at the peaks and troughs of HR deviating from the baseline
3 categories:
- Reassuring: 5-25 bpm
- Non-reassuring: <5bpm for 30-50 mins or >25 for 15-25mins
- Abnormal: <5 for 50mins, >25 for >25mins or sinusoidal
What are the causes of decreased variability of CTG ?
- Fetal sleeping
- Acidosis
- Tachycardia
- Drugs e.g. opiates, benzos
- Prematurity
- Congenital heart abnormalities
Define what accelerations on CTG are and the normal ranges
- These are abrupt increases in the baseline HR of > 15bpm for > 15secs
- They’re presence is reassuring, absence is non-reassuring
What are deccelerations on CTG and state the 3 main types
They are an abrupt decrease in baseline HR of >15bpm for >15secs
3 types:
- Late deccelerations
- Early deccelerations
- Variable deccelerations
Define what early deccelerations on CTG and state if they are pathological or not
- Early deccelerations start when the uterine contraction begins & stop when uterine contraction stops
- They are physiological
What are the concerning characteristics of a deceleration ?
- Lasting >60secs
- reduced variability within the deceleration
- No return to baseline HR
- Biphasic shape
- No shouldering
Define what variable decelerations are state if they are pathological or not
- They are observed as a rapid decrease in baseline HR with a variable recovery phase & duration. They may not have any relationship to uterine contractions
- Usually caused by umbilical cord compression (fetus not yet hypoxic and is adapting to reduced blood flow).
- Requires close monitoring but can sometimes resolve if mother changes position
They are non-reassuring when they are present ≥ 90mins, or with any concerning characteristics in up to 50% of contractions for ≥ 30mins, or with any concerning characteristics in over 50% for <30mins
They are abnormal if they have concerning characteristics in over 50% of contractions for 30mins
Define what late deccelerations are and state whether or not they are pathological
- Late deccelerations begin at peak of uterine contrac tion & rdcover after contraction ends
- They indicate insufficient blood flow to the uterus & placenta, resulting in hypoxia and acidosis.
- The presence of them indicated need for fetal blood sampling, if sampling acidotic then shows sig. fetal hypoxia and emergency c-section needed
Non-reassuring if in over 50% of contractions for <30mins with no risk factors
Abnormal if for 30mins (or less with any maternal or fetal risk factors)
Describe the classification of the overall impression of a CTG
- Classified as normal, non-reassuring or abnormal
- May need senior obstetric review to do so
Assess this CTG
Bra – 130
A – present
V – good ( > 5)
D – no decelerations
O - good
Assess this CTG
DR – High
C – 4/10
Bra – 170
A – none
Va – not great
D – late
O – very worried. Need to deliver baby
If Only 3 or 4 cm then she needs a section
List the management of fetal distress
- Change maternal position
- IV Fluids
- Stop syntocinon
- Scalp stimulation
- Consider tocolysis - Terbutaline 250 micrograms s/c
- Maternal assessment - Pulse / BP / Abdomen / VE
- Fetal blood sampling
- Operative Delivery
State what the results of fetal blood sampling indicates and therefore the subsequent management
pH < 7.20 indicates acidosis ==> severe hypoxia
What are the indications for instrumental delivery in labour ?
- Delay (failure to progress in stage 2)
- Fetal distress
- Maternal cardiac disease
- Severe PET / Eclampsia
- Intra-partum haemorrhage
- Umbilical cord prolapse Stage 2
What are the 2 options for instrumental delivery and state there pros and cons
Forceps or ventouse
There is no differences in CS rates, Apgar Score, long-term outcomes. Use the most appropriate instrument for individual circumstances
Ventouse is associated with:
- Increased failure
- Increased cephalohaematoma
- increased retinal haemorrhage
- Increased maternal worry
- Decreased Anaesthesia
- Decreased Vaginal trauma
- Decreased Perineal Pain
What are the indications for C-section ?
- previous CS
- fetal distress
- failure to progress in labour
- breech presentation
- maternal request
How much riskier is a C-section than other modes of delivery ?
4 X greater maternal mortality associated with CS
What are the potential complications of c-section?
sepsis, haemorrhage, VTE, trauma, transient tachyponea of newborn, subfertility, regret, complications in future pregnancy
State the management of delay in stage 1 of labour
Transfer from mid-wife led care to obstetric led care
- 1st line = Aminotomy if intact membranes
- 2nd line = oxytocin (1st line if membranes intact)
State the management of delay in stage 2 of labour
- 1st line = oxytocin if contractions inadequate
- 2nd line = instrumental birth (if presenting part inline or below ischial spines)
- 3rd line = c-section
