Normal Labour and Puerperium Flashcards
Define what labour is
A physiological process during which the fetus, membranes, umbilical cord & placenta are expelled from the uterus
What associated things occur during labour ?
- Regular, painful uterine contractions with increasing frequency, intensity and duration
- Biochemical changes in the cervical tissue allowing cervical effacement and cervical dilatation
What are the 3 key factors during labour ?
- POWER - Uterine Contraction
- PASSAGE - Maternal Pelvis – some are more suitable than others
- PASSENGER - Fetus
What are the 3 main hormones involved during labour?
- Progesterone
- Estrogen
- Oxytocin
What is the effect of progesterone during labour ?
It decreases uterine contractility by preventing gap junction formation and ==> hindering contracility of myocytes
What is the effect of estrogen during labour?
- It increases uterine contractility
- It also promotes prostaglandin production which further increases uterine contractility
What is the effect of oxytocin during labour ?
- It initiates and sustains uterine contractions (it acts on decidual tissue to promote prostaglandin release ==> increases uterine contractility)
The exact cause for the initation of labour is unclear, however list some of the potential factors which could cause it ?
- Change in the estrogen/progesterone ratio
- Fetal adrenals and pituitary hormones may control the timing
- Myometrial stretch (as uterus gets bigger) increases excitability of myometrial fibres
- Mechanical stretch of cervix and stripping of fetal membranes
- Fergusons Reflex = neuroendocrine reflex comprising the self-sustaining (positive feedback) cycle of uterine contractions initiated by pressure at the cervix or vaginal walls
- Pulmonary surfactant secreted into amniotic fluid
- Increase in production of fetal cortisol stimulates an increase in maternal estriol
- Increase in myometrial oxytocin receptors and their activation ==> increased uterine contractility
What is the bishops score used for ?
It is the best and simplest method used to assist in predicting whether or not induction of labour will be required/is safe
What are the 5 elements of the bishops score ?
- Cervix position - post, mid, or ant.
- Cervical consistency - firm, medium or soft
- Cervical effacement
- Cervical dilatation
- Station of body in pelvis
How many stages of labour are there ?
3 main stages
What is the 1st stage of labour divided up into ?
The latent and active phases
Define the latent stage of labour
- This is the start of labour up to 3-4cm dilated
- There is mild irregular contractions, cervix shortens and softens.
How long does the latent stage of labour last ?
This stage duration is variable and may take up to a few days
Define the active phase of labour
- This is from 4cm dilation until full dilation
- During this stage contractions are progressively more rhythmic and stronger and slow descent of the baby begins
State what normal progress is during the active phase and also what factors may affect this
- 1-2cm of increased dilatation per hour
- Analgesia, movement and parity all cause variability in this
Define the second stage of labour
Starts from full dilatation (10cm) to delivery of the baby
What is the normal duration of the second stage 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
Define what a nulliparous women is
A women who has never given birth before, also applies to women who have had stillbirths or a baby whom was not able to survive outside the womb
Define the 3rd stage of labour
Starts from time of delivery of the baby until expulsion of the placenta and fetal membranes
What is the normal duration of the 3rd stage of labour ?
Usually takes 10mins
What are the 2 options for management of the 3rd stage of labour ?
Active or expectant management
Describe what active management is
- This is where oxytocin or syntometerine (oxytocin + ergometerine) is administered following birth of the anterior shoulder or immediately after the birth of the baby
- Cord clamping and cutting after 1-5mins after birth
- Controlled cord traction - placenta pulled out once its separated from the uterus
- Bladder emptying
Note For active management, administer oxytocin by IM injection with the birth of the anterior shoulder or immediately after the birth of the baby and before the cord is clamped and cut. Use oxytocin as it is associated with fewer side effects than oxytocin plus ergometrine
Describe what expectant management of the 3rd stage of labour is
- spontaneous delivery of the placenta
- Cord is clamped and cut once its stopped pulsating
- You push placenta out with contractions - can take up to an hour
Which is the preferred option for the management of the 3rd stage of labour and why?
Active management - because it lowers the risk of post-partum haemorrhage (PPH)
When is the 3rd stage of labour considered prolonged and what is then done ?
After 1hr - preparation is then made for removal under GA
What are the cervical physiological changes which go on during labour to allow for dilatation and effacement
- Cervical softening due to increase in hyaluronic acid
- Cervical ripening due decrease in collagen fibre alignment & strength
What are the 2 types of contractions someone may experience during pregnancy (not just talking about labour now)
Braxton-hicks contractions & true labour contractions
Define what braxton hicks contractions are and when they occur
- They are intermittent weak contractions of the uterus which are irregular and do not increase in frequency or intensity
- They also resolve with change in position or activity
- The can start 6wks into pregnancy but are usually felt in the 3rd trimester
Why are braxton hicks contractions thought to occur ?
Thought to be associated with increased tightening of uterine muscles and preparation for birth
When do true labour contractions occur?
When your body releases oxytocin which stimulates uterus to contract
Describe true labour contractions, how you identify them and
- Feeling is described as a wave pain which starts low & rises then ebs away
- Mothers abdomen feels hard during them
- Real contractions get more painful (as labour goes on) and don’t resolve with a change in position
- There is accompanied cervical changes - softening, effacement and dilatation
How frequent are true labour contrctions and how long do they last?
Contractions start about 5-10mins apart (regular so evenly spaced time between them) this progressively gets shorter and they also increase in duration e.g. 10s to 45secs
Describe how uterine contractions are initiated and occur
- There is 2 pacemakers known as the tubal ostia (the 2 openings of tubules into the uterus) which spread synchronised waves downwards resulting in contractions
- The upper segment of the uterus contracts and retracts, whilst the lower sefement and cervix stretch, dilate and relax
Describe the intensity, frequency and duration of true labour contractions
- Maximum in 2nd stage of pregnancy
- Frequency - normal is up to 3-4 in 10 mins to allow time for resting tone
- Duration - Initially 10-15 secs and builds up to a Max of 45 secs
Progressively more intense, frequent and longer lasting
Go over describing abdominal fifths
- For this the head must be in the cephalic ppresentation
- The head is divided into fifths (about 2cm each) and you are basically palpating the abdomen to see how much of the head is palpable superior to the symphysis pubis
What are the 5 key parameters to assess during vaginal examination during labour?
- Effacement
- Dilatation
- Firmness
- Position
- Level of the presenting part or station
Most of the time the presenting part in normal presentation of the baby i.e. head first, the head is flexed so what part of the babies skull are you looking at ?
The posterior fontanelle
When assessing the descent of the babies head during labour what information do you need to observe?
- Abdominal fifths
- Maternal discomfort and feeling of pressure
- Frontal synciput and occipital eminences
- Vaginal examinations for cervical assessment
How frequently should vaginal exammination be carried out during normal labour ?
Every 4hrs
Go over the normal fetal positions during labour from a cephalic presentation
Note ROA = right occiput anterior
What is the normal position of the fetus during labour
- A longitudinal lie with cephalic presentation ==> The presenting part is then the vertex (head)
- Position is the occipito-anterior, head then engages in occipito-transverse position and then moves into OA position with a flexed head.
List some of the abnormal fetal positions
- Breech
- Oblique
- Transverse
- Occipito-posterior
What is the function of the aminotic fluid?
To nuture, protect & facilitates movement of the fetus
When can rupture of the fetal membranes (amniotic sac) occur ?
Timing of rupture of fetal membranes can occur anywhere from pre-term all the way to the baby being born in caul (born in the membranes)
Briefly go over the stages of decent of the baby during labour (covered properly in different lecture)
- Engagement
- Decent
- Flexion
- Internal Rotation
- Crowning and extension
- Restitution and external rotation (head adopts optimal position for shoulder)
- Expulsion, anterior shoulder usually delivered first
Describe what crowning is
This is the appearance of a large segment of the fetal head at the vaginal opening - Burning and stinging feeling felt by the mother
What is the common procedure done in certain cases to prevent trauma to the anal sphincters during crowning ?
An episiotomy - usually a mediolateral one
What are the 3 classic signs which indicate placental separation (occuring in the 3rd stage of labour)
- Uterus contracts, hardens and rises
- Umbilical cord lengthens permanently
- Gush of blood variable in amount
What are the analgesia options in labour ?
- 1st = paracetamol/ co-codamol
- 2nd = Entonox
- 3rd = Diamorphine
- 4th = Epidural, spinal or combined spinal/epidural
Support, massage/relaxation techniques may be used
Note TENS should not be offered in established labour
What is the normal volumes of blood loss during labour ?
- Normal = < 500mls
- Abnormal = > 500mls
- More significance if greater than 1,500mls
Note - Any blood loss prior to delivery apart from “show” is abnormal and requires referral to consultant unit
Following placental separation how is homeostasis achieved i.e. preventing excessive blood loss (PPH):
- Tonic contraction: Lattice pattern of uterine muscle strangulates the blood vessels (like putting pressure on a wound)
- Thrombosis of the torn vessel ends: pregnancy is a hyper-coaguable state
Define what the period puerperium is
It is the period of repiar and recovery post childbirth during which the mothers repro organs return to their original non-pregnant condition during 6 weeks post delivery
What is lochia
This is vaginal bleeding after birth which lasts for 10-14 days, it contains blood, mucous and endometrial castings
During the puerperium what happens to the uterus
Uterine involution occurs - its weight decreases, fundal height decreases back to normal and endometrium regenerates
What happens to the cervix, vagina and perineum after pregnancy ?
Regression occurs but never back to pre-pregnancy state
Describe the physiological diuresis which occurs post delivery?
There is an excessive/increase in urine 2-3 days postnatally
How is lactation initiated by the expulsion of the placenta ?
As there is a decrease in oestrogen and progesterone but prolactin stays the same therefore stimulating milk production
What is the importance of colostrum (first breast milk)?
It is rich in IgA ==> important for immunity
What are the potential problems with entenox (NO)?
Nausea and light-headedness
What are the potential problems experienced with diamorphine ?
- Nausea
- Drowsy
- Resp depression
What drug should be given alongside diamorphine ?
An anti-emetic
When rapid analgesia is required what is used ?
A combined spinal-epidural
How effective is an epidural in providing pain relief during labour ?
95% effective
What may an epidural inhibit?
Progress in stage 2 of labour - note however it does not impair uterine activity or prolong stage 1
What drugs are usually used in epidural analgesia ?
Levobupivacine (local anaesthetic) +/- opiate usually fentayl
What are the main complications of epidural analgesia ?
- Hypotension and Atopnic bladder (large dilated bladder that doesn’t empty) - main ones
- Dural puncture
- Headache
- Back pain
