Normal Labour Flashcards
How is labour defined?
- the physiological process in which a foetus is expelled from the uterus
- it requires the presence of regular uterine contractions
- these increase in frequency, intensity + duration
- this leads to progressive cervical effacement + dilatation
labour = regular contractions + cervical effacement / dilatation
other features (e.g. waters breaking) do NOT indicate labour
When does labour + delivery typically occur?
between 37 and 42 weeks gestation
Why is the position of the baby important during labour?
- the head pushes against the cervix, causing it to stretch
- stretching of the cervix sends nerve impulses to the brain
- the brain stimulates the pituitary gland to release oxytocin
- oxytocin causes the uterus to contract
if the baby is not in the correct position, the head is unable to cause the cervix to stretch
What are the 2 phases of labour?
- latent phase
- established phase
the established phase is further divided into 3 stages
What happens during the latent phase of labour?
- there may be some painful contractions, but these are irregular
- there may be some cervical effacement and dilation up to 4cm
- this phase can last from hours up to a week
during this phase women are encouraged to mobilise, use paracetamol and stay hydrated
What is meant by the established phase of labour?
- there are regular painful cervical contractions
- there is progressive cervical dilatation from 4cm
How can established labour be divided into 3 stages?
first stage:
- from the onset of labour (4cm dilation / true contractions) until 10cm dilation
second stage:
- from 10cm dilation to delivery of the baby
third stage:
- from delivery of the baby until delivery of the placenta
What is the first stage of labour?
- this begins when the cervix reaches 4cm dilation and true contractions begin
- there is cervical dilatation (up to 10cm) and effacement
effacement = cervix becomes thinner
What is meant by cervical effacement?
- also referred to as “ripening”
- the cervix becomes softer, thinner and shorter
it is assessed via a digital examination
- finger inserted into the cervical os to assess how dilated / effaced the cervix is
What is meant by the “show”?
- there is a mucus plug in the cervix that prevents bacteria from entering the uterus during pregnancy
- this falls out during the first stage of labour
- this creates space for the baby to pass through
this appears as a single blob of pinkish / white jelly which can be blood-tinged
What are the signs of the onset of labour?
- show (mucus plug from the cervix)
- rupture of membranes
- regular, painful contractions
- dilation of the cervix on examination
What are the criteria for diagnosing the latent and established first stage of labour?
latent stage:
- painful contractions
- effacement + dilation of the cervix up to 4cm
established phase:
- REGULAR, painful contractions
- dilation of the cervix from 4cm onwards
What are Braxton-Hicks contractions?
- occassional irregular contractions of the uterus
- felt during the 2nd or 3rd trimester
- there is temporary and irregular tightening / mild cramping in the abdomen
they are sometimes called “false labour pains” and can be described to feel like menstrual cramps
How are Braxton-Hicks contractions related to labour?
- these contractions are NOT true contractions and DO NOT indicate the onset of labour
- they do not progress
- they do not become regular
staying hydrated / relaxed can reduce these contractions
During vaginal examination in labour, what else is assessed?
descent of the head
- this is assessed in relation to the ischial spines of the pelvis
- it is called the “station of the head”
- in early labour, the station is often -1
- the station becomes +1 during the second stage (below the ischial spines)
Other than by vaginal examination, how can descent of the head be assessed?
abdominal palpation
- it is described by how many 5ths of the baby’s head can be felt above the pelvis
When describing descent of the head, what is meant by 5/5 and 0/5?
5/5th palpable:
- all of the head is above the pubic bone
- all 5 fifths can be palpated
0/5th palpable:
- all of the head is below the pubic brim and cannot be palpated
- once the cervix is 10cm dilated, usually none of the head is felt
What are women encouraged to do during the first stage of labour?
- walk and remain in an upright position
- this has been seen to reduce the duration of labour, need for C-section and epidural
How can the second stage of labour be divided into 2 stages?
passive stage:
- the cervix is fully dilated to 10cm
- there is an absence of contractions
active stage:
- there are expulsive contractions / active maternal effort alongside full dilation of the cervix
Why does the passive stage of the second stage of labour occur?
- once the cervix is dilated to 10cm, the head moves down the pelvis and applies pressure to the pelvic floor
- pressure on the pelvic floor produces the urge to push
- it can take time for this urge to occur when the head is still high
What are the 2 approaches to the third stage of labour?
- physiological management
- active management
What is meant by physiological management in the third stage of labour?
- the placenta is delivered via maternal effort alone
- uterotonic drugs are not used
- there is no cord traction
What is meant by active management of the third stage?
- there is assistance in delivery of the placenta
- IM oxytocin is given to encourage the uterus to contract
- traction is applied to the umbilical cord to guide the placenta out
Who is offered active management of the third stage and why?
- it is offered to all women routinely to reduce the risk of postpartum haemorrhage
- it will be initiated if there is haemorrhage
OR
- a > 60 min delay in delivery of the placenta
What is the major side effect of active management of the third stage?
N&V
How is active management of the third stage initiated?
- an IM dose of oxytocin (10 IU) is given
- this is given immediately after delivery of the baby
- other uterotonic drugs - such as syntometrine - can be used
When should the cord be clamped in active management of the third stage?
- the cord should be clamped + cut within 5 mins of birth
- there should be a delay of 1-3 mins between delivery and clamping to allow blood to flow to the baby
- (unless baby requires resuscitation)
delay is important in prevention of neonatal anaemia
How is controlled cord traction acheived?
- the abdomen is palpated to assess for a uterine contraction
- traction is applied DURING contractions
- it should be stopped if there is resistance
- at the same time, the other hand presses the uterus upwards (in the opposite direction) to prevent prolapse
the aim is to deliver the placenta in one piece
What should be done following active management of the third stage?
- massage the uterus until it is contracted and firm
- examine the placenta to ensure it is complete and no tissue remains in the uterus
What are the 3 important things to monitor in the mother?
- contractions
- vaginal loss
- vital signs
Why is it important to monitor contractions?
- frequency, strength and length of contractions gives a good indication of progress in labour
- 4-5 contractions in 10mins are needed to progress in labour
Why is it important to monitor vaginal loss?
- spontaneous rupture of the membranes (SROM) can occur at any point in labour (and before)
- once ruptured, observe for meconium or heavy blood staining
- this could indicate antepartum haemorrhage
How is the foetus monitored during labour?
low risk women:
- intermittent auscultation of the foetal heart
- via Doppler USS or Pinard stethoscope
high risk women:
- continuous monitoring via cardiotocograph (CTG)
