Normal Labour Flashcards
Labour is a physiological process during which what gets expelled?
The foetus, membranes, umbilical cord and placenta
Labour is usually associated with what physical symptom? Describe what happens to this as labour progresses?
Painful uterine contractions which increase in frequency, intensity and duration as labour progresses
What are the two main cervical changes which occur during labour?
Cervical effacement and dilatation
What are the main options about where to birth?
Consultant led unit, midwife led unit or homebirth
What is recommended with regards to making a birth plan?
Women are encouraged to make a birth plan but don’t have to
A change in the ratio of which hormones may be responsible for the onset of labour?
Oestrogen and progesterone
What foetal factors may control the onset of labour?
Foetal adrenal and pituitary hormones, as well as surfactant production secreted into the amniotic fluid
What is Ferguson’s reflex?
The positive feedback cycle of uterine contractions initiated by pressure at the cervix or vaginal walls
What are the roles of oestrogen in initiating labour?
Promote uterine contractions and prostaglandin production
What are the roles of oxytocin in initiating labour?
Initiate and sustain contractions and promote prostaglandin release
Where is oxytocin synthesised at delivery?
In decidual and extraembryonic foetal tissue as well as in the placenta
The number of oxytocin receptors where increase towards the end of delivery?
In the decidual and myometrial tissue
An increase in foetal cortisol triggers an increase in which maternal hormone?
Oestriol
When can the membranes rupture?
Pre-term, pre-labour, 1st stage, 2nd stage or baby can be born in a caul
Cervical tissue is formed of what?
Mostly collagen 1-4, but also smooth muscle and elastin held together by ground substance
What are the two phases of the first stage of labour? What defines them both?
Latent phase (up to 3-4cm dilated) and active phase (4-10cm dilatation)
What defines the timing of the second stage of labour?
Full dilatation to delivery of the baby
What defines the timing of the third stage of labour?
Lasts from the delivery of the baby to the expulsion of the placenta and membranes
Describe the contractions in the latent first phase of labour?
Mild and irregular
What happens to the cervix in the latent first phase of labour?
It shortens and softens - by the end of this phase the cervix is fully effaced
What is the duration of the latent first phase of labour?
Very variable - can last up to a few days
What happens to the uterine contractions in the active first phase of labour?
They become more rhythmic and stronger
What would count as normal progress in the active phase of the 1st stage of labour?
Dilating by 1-2cm per hour
What happens to the cervix in the active phase of the 1st stage of labour?
It dilates to 10cm (full dilatation)
In nulliparous women, the second stage of labour would be considered prolonged after how long if the woman a) had regional anaesthesia? b) did not have regional anaesthesia?
a) 3 hours b) 2 hours
In multiparous women, the second stage of labour would be considered prolonged after how long if the woman a) had regional anaesthesia? b) did not have regional anaesthesia?
a) 2 hours b) 1 hour
Are vaginal examinations always carried out to assess the time of full dilatation?
No, not always in a low risk case
What is the average duration of the 3rd stage of labour?
10 mins
If the placenta hasn’t been delivered within 1 hour of delivering the baby, what should happen?
Preparation for removal under GA
What is expectant management for the 3rd stage of labour?
Spontaneous delivery of the placenta
What is active management for the 3rd stage of labour?
The use of oxytocic drugs and controlled cord traction
What are the 5 elements of the Bishop’s score?
Cervical position, consistency, effacement, dilatation and station
Describe the cervical positions and what score they would give you in the Bishop’s score?
Posterior = 0, mid-position = 1, anterior = 2
Describe the cervical consistencies and what score they would give you in the Bishop’s score?
Firm = 0, medium = 1, soft = 2
Describe the cervical effacements and what score they would give you in the Bishop’s score?
0-30% = 0, 30-50% = 1, 60-70% = 2, > 80% = 3
Describe the cervical dilatations and what score they would give you in the Bishop’s score?
Closed = 0, 1-2cm = 1, 3-4cm = 2, > 5cm, = 3
Describe the cervical stations and what score they would give you in the Bishop’s score?
-3 = 0, -2 = 1, -1 = 2, 1/2 = 3
A Bishop’s score of < 5 indicates what?
Labour is unlikely to start without induction
A Bishop’s score of > 9 suggests what?
Labour will most likely commence spontaneously
Braxton-Hicks contractions can also be known as what? Why?
False labour - because they give the woman a false sensation that she is in real labour
What causes Braxton-Hicks contractions?
Tightening of the uterine muscles which is thought to aid the body to prepare for birth
When can Braxton-Hicks contractions occur?
Can start 6 weeks into pregnancy but are usually more commonly felt in the 3rd trimester
Describe a Braxton-Hicks contraction?
Irregular, do not increase in frequency or intensity, relatively painless
What can make Braxton-Hicks contractions better?
Light activity
True labour contractions occur under the influence of what?
Release of oxytocin
What is true labour?
When the contractions become evenly spaced and the time between them gets shorter and shorter
What are the 3 key factors of labour?
Power, passage and passenger
Where is the highest density of uterine smooth muscle found? Waves from uterine contractions pass in which direction?
At the fundus / in a downward direction
Up to how many uterine contractions in 10 minutes is normal?
3-4
What is the normal duration of a uterine contraction? What is the duration when it reaches its maximum?
10-15 secs / 45 secs
When do maximum intensity uterine contractions occur?
In the second stage
What is the most suitable female pelvic shape for vaginal delivery?
Gynaecoid
Describe what an anthropoid pelvis looks like?
Oval shaped inlet with large AP diameter and small transverse diameter
Describe what an android pelvis looks like?
Triangular or heart shaped inlet and is narrower at the front
Women of which ethnic origin are more at risk of an android pelvis?
Afro-Caribbean
What would be the normal/ideal way for each of the following to be: a) foetal lie? b) foetal presentation? c) presenting part? d) foetal position?
a) longitudinal b) cephalic c) vertex d) OA
How should the baby’s head ideally be during delivery?
Flexed
What would be the abnormal way for each of the following to be at delivery: a) foetal lie? b) foetal presentation? c) foetal position?
a) transverse or oblique b) breech c) OP
How can the baby’s position be determined during labour?
Fontanelles can be felt on vaginal examination
What are the 7 cardinal movements of labour?
Engagement, descent, flexion, internal rotation, extension (crowning), restitution and external rotation, expulsion
What is engagement?
The passage of the widest part of the foetal head to a level below the pelvic inlet
The foetal head is engaged when?
3/5ths of foetus has entered the pelvis and 2/5ths are still in the abdomen
What is descent?
Downward passage of the presenting part through the pelvis
As the foetal head engages and descends, what pelvic diameter is the largest? For this reason, what position should the baby’s head be in?
Transverse diameter of the pelvis is larger at the pelvic inlet / baby’s head should be in an occiput-transverse position
In normal labour, how often should vaginal examinations be carried out?
Every 4 hours
Why does flexion of the foetal head occur?
Occurs passively as the head descends due to resistance from the pelvic floor
Describe the internal rotation that occurs as a foetus passes through the birth canal?
Rotation from the transverse to anterior position (i.e. facing mother’s back)
Why does the foetus internally rotate during delivery?
As it reaches the pelvic outlet, the AP diameter is wider than the transverse diameter
When is crowning said to occur? What foetal movement does this trigger?
When the foetus has reached the level of the introitus, allows foetal head extension
What part of the foetal head delivers first?
Occiput
Once the baby’s head has been delivered, what movement occurs?
External rotation (away from the mother’s back)
What happens in expulsion?
The rest of the foetal body is delivered: anterior shoulder first, then posterior shoulder and then the rest of the body
When the baby is crowning, how will this feel for the mother?
Burning and stinging
How should delivery of the head be managed?
You should be guiding but not leading to prevent rapid extension of tissues and perineal tearing
What may be required to prevent trauma to the anal sphincter?
An episiotomy
What is a partogram?
A graphic record of key data contained on one sheet
What factors are comprised on a partogram?
Maternal observations, cervical dilatation and foetal wellbeing
How often should each of the following be measured during delivery: a) frequency of contractions? b) maternal pulse? c) maternal BP and temp?
a) every 30 mins b) hourly c) 4 hourly
