Intrapartum care & labour Flashcards
What is this defining: the process of uterine contractions and cervical dilation that enables the uterus to deliver the viable foetus (>24wks), placenta and membranes?
Labour!
When is labour diagnosed?
When there are
- regular and
- increasing painful contractions
- at least every 5 mins
that brings about progressive cervical effacement & dilation
when a blood stained mucus plug is passed from the cervix this is called loss of “show”.
does this indicate labour?
no.
labour = regular and increasing painful contractions (5mins), loss of show doesnt define lanbour
NOR DOES SPONTANEOUS RUPTURE OF MEMBRANES (SROM)
although these events may happen around the same time…
When does “normal labour” occur?
at term which = 37 - 42 weeks
should have a spontaneous, smooth progression of contraction and dilation, cephalic presentation, spontaneous vaginal delivery with minimal complications for mother/baby
What are the main problems if “normal” labour doesn’t occur? (~37-42wks etc)
if pre term: baby can have Acute respiratory distress sydnrome (ARDS) and complications of prematurity
if after term: the placenta begins to die
What stage of labour does latent and established phase come under?
the first stage
What stage of labour does active and passive come under?
the 2nd stage
What is the 3rd stage of labour?
delivery of the placenta
What is the first stage of labour - the latent phase?
- painful, often irregular contractions
- the cervix is effacing (becoming shorter and softer)
- & dilation –> 3/4cm
What is the first stage of labour - established phase?
regular contractions with dilatation from 3–>10cm @1cm/hr
What is the second stage of labour - passive?
complete cervical dilation e.g. to 10 cm but no pushing
What is the second stage of labour - active?
maternal pushing using the abdominal muscles and valsalva until the baby is born!
(valsalva = a woman is instructed to take a deep breath at the beginning of the contraction, to hold her breath and push as long and hard as she can in synchrony with her contractions.)
What do prostaglandins and oxytocin do in the uterus during labour?
they increase intracellular free calcium ions e.g. help with contraction
What organ in labour does this description refer to?
- must soften, shorten, thin out (effacement) and dilate
the cervix
What organ during labour does this refer to?
- must change to an active state of regular, strong, frequent contractions
- followed by a resting phase in order to maintain placental blood flow & adequate perfusion of the foetus
The uterus!
What changes happen to the upper segment of the uterus during labour?
there is progressive uterine SMC retraction (shortening) here
–> makes the thicker, actively contracting “upper segment”
What changes happen to the lower segment of the uterus in labour?
- the lower segment = thinner and more stretched
- until eventually the cervix is “taken up” e.g. effaced into the lower segment of the uterus
- so forming a continum with the lower uterine segment
How do you describe the frequency of contractions?
- describe the frequency per 10 min interval e.g. 2 in 10
- this increases to 4-5 in 10 mins during advanced labour
- duration varies from 30-60s
[NB: contractions are involuntary]
What changes do prostaglandins, interleukins and dermatan sulphate replacement cause in the cervix during labour?
They all cause cervical softening (“ripening”) so that contractions can cause effacement/dilatation
PG’s
- increase proteolytic activity
- decrease collagen & elastin
Interleukins:
- proinflammatory change with neutrophil invasion
hydrophilic hyaluronic acid replaceing dermatan sulphate:
- increase water content of cervix
What is the name of the graphic representation of the progress of labour?
partograms
What does the alert line on a partogram show?
it is drawn at 1cm/hr from the start of active phase (e.g. where maternal pushing using abdo musc. and valsalva until the baby is born)
– would show where the labour is starting to not progress
what does the action line on a partogram show?
it is parallell to the alert line but 2-3cm to the right
if labour progresses to the right of this line = slow labour and may need intervention
what intervention can be given if labour progresses to the right of the action line on a partogram?
- rupure membranes (help descend, PG release);
- artificial oxytocin
Apart from the alert and action line what else do partograms show?
Maternal parameters:
- pulse, BP, temp, urine output
Maternal labour:
- Rate of cervical dilation
- Descent of head
- Contraction frequency & duration
Foetal:
- heart rate
- Caput & moulding of head
What observations should be done on mum and baby during labour?
Mum -
- BP, temp
- contractions,
- bladder emptying (full bladder can hinder uterine contraction and if empty = more space for baby to go through)
- vaginal examination,
Baby -
- foetal heart rate & intermittent auscultation (IA)
- every 15 mins in 1st stage,
- 5 mins in 2nd stage (>10cm)
What is a cardiotocograph (CTG)?
- it uses a pressure transducer (tocodynamoter) positioned on the abdomen at the fundus of the uterus
- or foetal scalp electrode
- to produce a foetal ECG
- it assesses the frequency of contraction and their intensity/amplitude of uterine contractions (30-60mmHG)
What do these factors to mum and baby represent?
Mum:
- Previous C section
- Labour: IOL , Oxytocin augmentation, Epidural anaesthesia
- Medical: Maternal cardiac problems, PET or HTN, Diabetes of any type
- Obs: Prolonged rupture of membranes >24hrs; Post-maturity (>42wks) / Prematurity <37wks; APH or intrapartum haemorrhage; Pyrexia; Abnormal umbilical artery Dopplers
Baby:
- Small for gestational age
- Oligohydramnios
- Abnormal lie
- Multiple pregnancy
- Meconium-stained liquor
- Abnormality heard on intermittent auscultation
the indications for electronic foetal monitoring - cardiotocograph (CTG)
What is DR C BRAVADO to do with interpreting CTG’s?
- DR - define risk - why is woman having CTG?
- C - contractions - how many per 10mins
- BRA - baseline rate - normal foetal HR = 100-160bpm
- V - variability (of HR) - reduced if there is foetal hypoxia, malformation, magnesium & prematurity OR sleeping
- A - an up spike of >15bpm for >15s = reassuring, occurs when foetus is moving
- D - decelerations = down spike of >15bmp for >15s - can be normal with contractions
- O - overall: normal vs non-reassuring vs abnormal
are early decelerations that mimic the shape and timing of contractions caused by?
Head compression
What do late decelerations that happen after a peak of contraction represent?
are a sign of ACIDOSIS
–> do foetal blood sampling
What do shallow deceleratiopns with reduced variability mean?
needs intervention
What do variable “V” shaped decelerations with shoulders on each side represent?
Cord compression
What are atypical decelerations
e.g. loss of shouldering <60s, <60 beats from the baseline a sign of?
Foetal hypoxia
Where is foetal blood sampling taken from during labour and why?
- a small amount of blood is taken from foetal scalp
- it improves specificit of CTG in detecting foetal hyposia
- in signs of foetal hypoxia / signs of acidosis or if trace is abnormal
- UNLESS immediate deliver is required e.g. bradycardia or suspected LSCS scar rupture
When should foetal blood sampling not be taken?
- suspected ITP
- any blood bourne viruses
- use in caution with pyrexia
A foetal blood sampling gives PH of 7.3 is this normal?
yes, pH >7.25 is normal
so as foetal blood sampling is done due to an abnormal trace - repeat the FBS in 1hr if CTG remains abnormal
A foetal blood sample reads pH of 7.22 is this normal?
it is boarderline
as its between pH 7.21 - 7.24
repeat in 30 minutes if the CTG remains abnormal
A foetal blood sample gives the result of pH = 7.1. What should be done?
A pH < 7.20 indicates immediate delivery!
At the start of labour, what does the baby produce to cause reduction in progesterone, oxytocin release, increase in PG, ca2+ influx into the myometrial cella and CRH (CRH->acth->cortisol) production by the placenta?
baby produces steroids from its foetal adrenal glands
& produces foetal oxytocin
=
decrease in progesterone
increase in PG, oxytocin, placental CRH production and calcium influx into myometrial cells
Why does reducing progesterone (by babys steroids and oxytocin) matter?
higher E2:P ratio initiates and maintains labour
this is produced in the amnion, chorion, decidua & myometrium
can be triggered by oestrogen, sweem, SROM, infection and uterine activity
What should a pregnanct lady do if her waters break but there are no contractions?
- go home & come back in 24hrs or if spike a fever
- if there is a risk of infection
What is the difference between “true” and “false” labour?
false labour are where Braxton hicks contractions occur:
- they have varying frequency and strength
- they may stop
- there is no dilation
VS True labour:
- regular and strong contractions w/increasing frequency,
- they don’t stop and
- there is effacement–>dilation & descent of foetus
What are the pros and cons of home delivery?
- Relaxing & more comfortable environment
- No transport concerns
- 1:1 care guaranteed
- Medical interventions less likely
but this does mean that:
- Expert medical care less readily available & there
- are fewer options re: analgesia.
- also –> Long transfer time into hospital in case of maternal/neonatal emergency
Which stage of labour is shorter in multiparous women?
the latent phase of the first stage of labour
How long do the latent phase and established phase of 1st labour stage normally take?
the latent phase is normally 3-8 hours
the established phase is 2-6 hours
total 1st stage of labour = 5-14 hours
What is the definition of the first stage of labout?
the period of time between the first onset of regular painful uterine contractions –> full cervical dilation (10cm)
NB: after 2-4 cm dilation the rest of the dilation then occurs at a rate of 1 cm per hour
How much effacement and dilation occurs in the latent stage vs the established phase of the first stage of labour?
Latent phase cervix:
- effacement from 3cm–> <0.5cm
- dilation to 3cm
Established phase cervix:
- dilation from 3cm-10cm (1cm/hr)
What is the managment of the latent phase (1st Stg.) of labour?
- Reassurance (can take a while, especially in 1st time mums)
- nutrition, hydration
- pain relief (e.g. simple analgesia at this stage)
- ambulation (walking about), cervical sweep (separates membrane and cervix, releases PG’s to soften cervix)
- observation unless we suspect complication & compromise of mum or baby (caution of over-intervening)
What monitoring should be done for women in the first latent stage of labour?
Monitoring -
- every 15m: foetal HR
- 1/2hrly: assess contractions
- 4 hrly: BP & temp & vaginal exam
- (dilation, position, station of head),
- record urination
When should stronger pain relief start to be given during labour?
Whay pain relief?
1st stage - ESTABLISHED PHASE though
- gas & air,
- pethidine,
- epidural or
- water bath,
- TENS
What is the managment for the established phase of labour?
- reassurance
- hydration
- pain relief (G&A, pethidine etc)
- artificial rupture of membranes
- oxytocin
- monitoring
Why is urine checked for ketones in (established phase of Stg 1) labour?
ketones in the urine are a -ve marker for success in pregnancy
How is oxytocin used to stimulate labour?
titrate oxytocin dose based on uterine contractions
max contractions = 5 every 10 mins (every 2 mins), lasting no more than 1 min each
NB: beware oxytocin can hyperstimulate - this is dangerous as foetus is hypoxic during contractions “iatrogenic foetal distress”
What is the definition of “slow labour”?
- a delay in the first stage of labour
- (getting effacement and dilation)
- < 2 cm/h dilation in 4 hours
- (e.g. should be 4cm dilated in 4 hours e.g. 1cm/h after intial 3cm dilation)
What are the causes of slow labour?
the 3P’s!
-
Power
- e.g. inadequate uterine contractions (commonest cause)
-
Passage
- inadequate pelvis
- (e.g. shape, injury, tumour, osteomalacia, full bladder, constipation, fibroids, ovarian cysts)
-
Passenger
- large foetus or malposition
- foetus transverse head diameter = 10cm, AP = 14:(in birth enters transversely, 90 rotate, head extend; 90 deg for shoulder)
What are the problems / complications of having a slow labour?
- Maternal dehydration/exhaustion
- Maternal & foetal infection: more examinations & interventions
- Foetal distress
- Uterine rupture
- PPH
- Vesicovaginal fistulae
- Operative injury
- —> overally Morbidity
How do you augment slow labour?
- Amniotomy & reassessment at 2hrs
If SROM –>
- Oxytocin infusion (titrat based on not wanting >5 contractions every 10mins)
- Reassessment in 4hrs (continuous CTG)
NB:(offer epidural before starting oxytocin)
What phases is the second stage of labour split into?
passive and active phase
What is the definition for passive phase?
time between full dilation and the onset of involuntary explulsive contractions
- no maternal urge to push
- the foetal head is still relatively high in the pelvis
What is the definition for the active phase of labour?
- engaged head (; means only 1/5 or 2/5 of head palp. e.g. no occiput felt via abdo)
- pressure on stimulating nerves
- explosive urge to push (ferguson reflex)
- SROM
- difficulty in passing urine as bladder displaced and rectum pushed into
How long should the activer phase of labour last?
active labour shouldn’t last longer than:
- 1hr in multiparous
- ~2hrs in nulliparous
- >3hrs is assoc. with increased maternal & foetal morbidity
[NB: latent phase is shorter in multiparous woman]
What how does the process of baby being born during the active phase of labour go?
- head floating before engagement
- engagement, flexion, descent
- further descent, (occipito-transverse)
- internal rotation (90 degree rotation by levator ani - facing mums anus)
- complete rotation begining extension - extends neck under pubic arch
- complete extension - “crowning”
- restitution (external rotation e.g. rotates back in line with shoulders as they come out)
- delivery of anterior shoulder (pull baby down)
- delivery of posterior shoulder (pull baby up)
What should be done for the woman when the baby is “crowning” e.g. head in complete extension?
- tell woman to pant!
- so its slow to avoid a vaginal tear
- midwife/etc puts counter pressure on the perineum
- to help avoid tear
What is the management of the active stage of labour?
- Reassurance & explanation
- Positioning - left lateral position or all fours
- Slow crowing phase - panting
- Adequate analgesia (pethidine, G&A, epidural etc should be started from established phase!)
Monitoring -
- foetal HR every 5mins,
- assess contractions 1/2hrly
- vaginal exam hrly (dilation, position, station of head),
- BP hrly, & temp 4hrly,
- record urination
if there is:
- a prolonged 2nd stage,
- foetal distress,
- breech delivery
- <34 wks,
- face presentation,
- caput,
- instrumental delivery under GA
What are these indications for?
assisted delivery
vacuum (ventouse) or forceps
but most things else still need to be going fine e.g.
- Head <2/5ths palpable
- Not a large baby
- Cervix fully dilated & membranes ruptured
- No excessive capital/moulding
- Satisfactory foetal condition & presentation/position
- Empty bladder
- Descent with contraction & bearing down effort
What are the complications of assisted delivery?
- Maternal genital tract trauma - especially with forceps: including, obstetric sphincter injury
- Spiral vaginal tears with rotational forceps deliveries
- Fetal injuries with forceps (rare)
- Fetal injuries with ventouse
- Obstetric brachial plexus injury –> excessive lateral traction
If delivery not imminent after 3 pulls --> emergency C-section
What delivery method are these foetal injuries from?
- Facial nerve palsies
- Skull fractures
- Orbital injury
- Intracranial haemorrhage
injuries with forceps (rare though)
What delivery method are these foetal injuries from?
- Cephalhaematoma (most common, blood pooling under scalp)
- Retinal haemorrhage
- Scalp lacerations and scalp avulsions (torn off by trauma)
- more common if >3 pulls used
foetal injuries with ventouse
What is the defintiion of the third stage of labour?
From:
- delivery of the foetus
- to delivery of the placenta & membranes,
- usually within a few minutes of the birth of the baby
When is the most dangerous time for mum during labour & why?
When the placenta separates (3rd stage)…
- need contraction of the uterine muscles
- venous return from the uterus is reduced (babys circulation not pushing it?) causing congested + burst vessels
- need to deliver placenta
- need to feel for pulse in cord -> when its gone you can clamp it and cut
- wait for placenta to detach from uterus (& then can pull in a controlled manner)
- –> cord lengthens –> rush of blood per vaginum –> uterus rises –> uterus contracts in the abdomen
What active managment can be given to avoid bleeding in the third stage?
- IV syntometrine (oxytocin for ST contractions, ergometrin for LT contractions)
- 10 IU oxytocin IM if HTN –> NOT ergometrin = CI’d
use Controlled cord traction (pull) until placenta is delivered
- wait for placenta to separate (umbilical cord lengthens & there’s a spurt of blood)
- Placenta & membranes checked for completeness
- Estimate blood loss
- Check for tears & suture under local anaesthetic as required
- wait for placenta to separate (umbilical cord lengthens & there’s a spurt of blood)
If mum wants no active management can wait for up to an hour - but if any bleeding or signs of complications need to switch to active management
