Normal Labour Flashcards
What is normal labour?
The spontaneous process in which the foetus, placenta and membranes are expelled from the birth canal between 37-42 weeks of gestation with the baby’s vertex presenting and resulting in a spontaneous vaginal delivery
How is the initiation of labour triggered?
Paracrine and autocrine factors from the mother, baby and placenta lead to the following:
- Cervix softens
- Myometrial tone changes to allow for coordinated contractions
- Progesterone decreases whilst oxytocin and prostaglandins increase to allow for labour to initiate
What are the stages of labour?
Stage I- split into latent and established
Stage II- active and passive
Stage III
What processes occur during the latent first stage of labour?
The latent stage involves contractions that are irregular and short, and not usually painful at this point
What is involved in the established first stage of labour?
Established labour involves regular, painful contractions with varying lengths
When is the first stage of labour complete?
When the cervix is fully dilated at 10cm, with normal progress being 0.5-1.0cm per hour.
Between what processes is the second stage of labour?
Stage II of labour occurs between full dilatation of the cervix and the birth of the baby
What is the passive second stage of labour?
The passive stage is when the cervix is fully dilated but there are not yet any involuntary expulsive contractions
What is the active second stage of labour?
The active stage is when the presenting part is visible and there are involuntary expulsive contractions
How long after initiation of the active second stage of labour would birth be expected?
Primigravida- within two hours
Multigravida- within one hour
How long should the passive second stage of labour last?
The passive stage should be allowed to last for up to two hours before active maternal effort is started
Between what processes is the third stage of labour?
Stage III of labour occurs between the birth of the baby and the expulsion of the placenta and membranes
How long should the third stage of labour last?
Considered to be prolonged if not complete within 30 mins of birth with active management or 60 mins with physiological management
What active management can be given for stage III of labour?
Uterotonic drugs
Optimal cord clamping
Controlled cord traction
What passive management is involved in stage III of labour?
Delivery of placenta by maternal effort
Cord clamped once pulsation has stopped
No uterotonic drugs
What are the possible methods for monitoring progress of labour?
- Maternal observations
- Abdominal palpation (always done prior to vaginal exam)
- Vaginal examination
- Monitoring of liquor- colour (clear, faint pink or straw coloured all normal), smell etc
- Auscultation of the fetal heart (to be done every 15 minutes in stage I of labour and every 5 minutes in stage II or after every contraction)
- Palpation of uterine muscle contractions
- External signs e.g. Rhomboid of Michaelis (protruding coccyx when delivering baby) and anal cleft line (purple line running from buttocks and up spine)
How is CTG monitoring done and why is it helpful?
CTG monitoring is done using two receivers, one monitoring uterine contractions and one foetal heartbeat. These can be very helpful in noticing links between contractions and decreases of the baby’s heartbeat.
What processes are involved in the mechanism of labour?
- Descent
- Flexion
- Internal rotation of the head
- Crowning and extension of the head
- Restitution
- Internal rotation of the shoulders
- External rotation of the head
- Lateral flexion
What are the features of normal labour?
Longitudinal lie Attitude of good flexion Cephalic presentation LOA or ROA position Denominator is occiput Presenting part is anterior parietal bone
How is crowning defined?
Defined as when the vertex is going through the pelvic inlet and the head can be seen from the external. At crowning, the mother stops pushing to reduce stress on baby.
What analgesia can be given during labour?
- Breathing, massage, TENS, paracetamol and dihydrocodeine
- Water
- Entonox (inhalational nitrous oxide and oxygen)
- Opioids (morphine, diamorphine, pethidine)
- Remifentanil (patient-controlled analgesia)
- Epidural
- Consider maternal position and mobility as means of reducing pain and facilitating progress in labour
