Normal labour Flashcards
- To obtain an understanding of the process of normal labour and its associated problems
- To describe the process of normal labour
- To describe methods of assessing progress in labour
- To apply knowledge of the methods of anaesthesia and analgesia used in labour, their advantages and disadvantages
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Labour is the process in which the …, … and … are expelled
It is normally …, occurring at … weeks gestation
foetus, placenta and membranes are expelled
37-42 wks gestation
Normal
- lie
- presentation
Longitudinal
Cephalic/vertex
The initiation of labour is due to many physiological factors that are not fully understood
But some of the key physiological changes to allow expulsion are … (3)
Cervix softens
Myometrial tone changes to allow for coordinated contractions
Progesterone decreases whilst oxytocin and prostaglandins increase to allow for labour to initiate
How many stages of labour
3
Describe stage 1 of labour (3 partxs)
1st part is the LATENT PHASE where cervix softens and you may start feeling irregular contractions
2nd part is ESTABLISHED PHASE/ACTIVE PHASE when cervix dilates to at least 4cm from more regular and strong contractions
3rd part is TRANSITION PHASE towards the end of stage 1 labour when cervix is almost fully dilated; contractions are even more strong and frequent to dilate to 10cm
What does the cervix have to do during labour (4)
move forward, soften, efface, dilate
Describe stage II of labour
From full cervix dilation to pushing baby out of vagina
Involves the passive second stage where you may not feel an urge to push straightaway
Becomes the active second stage when you have the urge to push
For a primigravida birth (first time pregnancy), birth would be expected within how many hours of the ACTIVE SECOND STAGE
2 hours
For a multigravida birth (at least second time pregnancy), birth would be expected within how many hours of the ACTIVE SECOND STAGE
1 hour
Describe stage III of labour
Begins once your baby is born, and ends when you deliver the placenta and the empty bag of waters that are attached to the placenta (membranes)
Stage III of labour can even be actively managed or physiologically managed
-what does active management involve
routine use of uterotonic drugs, optimal cord clamping, controlled cord traction
Stage III of labour can even be actively managed or
-what does physiological management involve
no routine use of uterotonics, no cord clamping until pulsation has stopped, delivery of the placenta by maternal effort
Stage III is prolonged if it’s not completed within how long of active management, or within how long of physiological management
30 mins
60 mins
Methods of assessing progress in labour
Maternal observations
Abdo palpation - lie, presentation, engagement
Vaginal examination
Monitoring of amniotic fluid - should be clear
Auscultate foetal heart
Palpation of uterine contractions
Continuous monitoring of labour could be done with
Cardiotocograph - monitors foetal HR and strength of contractions
Preferred position of baby’s head
Occiput anterior
-left OA has reputation for being best to help baby be in smallest diameter to fit through pelvis
Mechanism of labour (9)
Descent Engagement Neck flexion Internal rotation of head Crowning Extension of the presenting part (head) Restitution + external rotation Internal rotation of shoulders Lateral flexion
Describe the mechanism of labour
- descent
- engagement
Head descends through pelvic inlet to pelvic floor
Engagement occurs when the largest diameter of the fetal head descends into the maternal pelvis; engaged when 3/5 or less palpable in abdo. As head engages, it moves toward pelvic brim in either left/right occipito-transverse position
Describe the mechanism of labour following descent + engagement
- neck flexion
- internal rotation of head
- crowning
When the occiput comes into contact with pelvic floor, foetal neck flexes (chin to chest) which allows smallest diameter through pelvis
Head rotates from left/right occipito-transverse to occipito-anterior
When the widest diameter of the foetal head successfully goes through the narrowest part of the maternal bony pelvis, the foetal head is considered to be ‘crowning’. (when head is visible at vulva and no longer retreats back between contractions)
Describe the mechanism of labour following descent, engagement, neck flexion, internal rotation + crowning
- extension
- restitution
- internal rotation of shoulders
Occiput slips out beneath suprapubic arch allowing head to extend
Baby will naturally align its head with the shoulders (restitution) by externally rotating the face to face left or right medial thigh
Once the shoulders have reached pelvic floor, they will complete rotation from transverse to anterior-posterior
Analgesia used in labour
TENS
Paracetamol/dihydrocodeince
Entonox (nitrous oxide + oxygen, ‘gas + air’)
Opioids (morphine etc)
Remifentanil patient controlled - press button to deliver dose
Epidural
