Normal labour Flashcards
Define labour.
Labour is the process in which the fetus, placenta and membranes are expelled via the birth canal.
Normal labour description.
- Spontaneous
- 37-42 weeks gestation
- foetus presenting by the vertex
- Results in a spontaneous vaginal delivery (SVD)
What key physiological changes must occur to allow for expulsion of the foetus?
- Cervix softens
- Myometrial tone changes to allow for coordinated contractions
- Progesterone decreases whilst oxytocin and prostaglandins increase to allow for labour to initiate
Define stage I of labour.
Time from the onset of labor until complete dilation of the cervix has occurred.
Stage I latent phase.
Occurs during onset of labor, ends at 6 cm of cervical dilation. Characterized by mild, infrequent, irregular contractions with gradual change in cervical dilation (< 1 cm per hour).
Stage I active phase.
Occurs after the latent phase at ≥ 6 cm of cervical dilation, ends with complete (∼ 10 cm) cervical dilation. Characterized by an increase in the rate of cervical dilation (1–4 cm per hour).
Anticipated progress of stage I of labour.
0.5 – 1.0 cm per hour.
Definition of stage II of labour.
From full cervical dilatation to the birth of the baby.
How long should the active second stage of labour last?
- Primigravida birth would be expected within two hours of active second stage
- Multigravida birth would be expected within one hour of active second stage
Definition of stage III of labour.
The time from the birth of the baby to the expulsion of the placenta and membranes.
What is prolonged third stage of labour?
If it is not completed within 30 minutes of the birth with active management or within 60 minutes of the birth with physiological management.
What does active management of the 3rd stage involve?
- Early clamping and cutting of the umbilical cord (now routine practice is to allow 2-5 minutes of delayed cord clamping for all women unless contraindicated)
- Use of uterotonic medications
- Delivery of the placenta by controlled cord traction
Which drugs does the active management of the 3rd stage use?
- Syntometrine
- Oxytocin
Progress and monitoring
- Maternal observations
- Abdominal palpation
- Vaginal examination
- Monitoring of liquor
- Auscultation of the fetal heart
- Palpation of uterine muscle contractions
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
Non pharmacological analgesia.
- breathing exercises
- aromatherapy
- water
- hyponobaby
- TENS machine
Simple analgesia
- paracetamol
- dihydocodeine
- aspirin
Other analgesia
- Entonox - nitrous oxide
- opiates
- epidural
- spinal anaesthesia
Paracetamol
Safe throughout pregnancy; may be used in latent phase of labour for pain relief
Dihydrocodiene
- May be useful in latent phase of labour
- Make sure patient aware of side effects (nausea, constipation, drowsiness)
- Risk of neonatal respiratory depression
Aspirin
Avoid in labour for acute pain relief as it increases bleeding risk
Risks from taking NSAIDs in pregnancy
- premature closure of the foetal ductus arteriosus
- foetal oliguria
- oligohydramnios after 30 weeks gestation
- bleeding in foetus
Entonox
- Patient can self-administer during contractions by inhaling through a mouthpiece attached to the wall
- Quick onset, short half-life
- Usually reserved until in active labour
Opiates
- Can cause nausea and vomiting, drowsiness and respiratory depression in the woman
- Can cause neonatal respiratory depression
- Usually co-prescribe with an antiemetic
- example is Remifentanyl PCA (Patient controlled analgesia)
