FOAMed tutorial on labour as seen on http://kecha5.wix.com/communitycollege

1. Kate Charters
WHERE DO BABIES
COME FROM?

2. Labour
• Definition: Natural process that culminates in the delivery of one or
more infants. Retrospective diagnosis.
• Spontaneous onset of labour at term is typically between 37 and 42
weeks.

3. Variables
• Passage: Maternal bony pelvis
• Power: Uterine contractions
• Passenger: Foetus

4. Passage
• Pelvic inlet: Bounded by the sacral
promontory, iliopectineal line and
symphysis pubis. Greatest diameter is the
transverse plane ~13.5cm.
• Pelvic outlet: Bounded by the pubic arch,
ischial tuberosities, tip of the coccyx and
the sacrotuberous ligament. Greatest
diameter is the AP diameter at 13cm.
• Plane of least dimensions: Bounded by the
lower border of the symphysis pubis, the
sacrum and the ischial spines.
• Once the head has descended past the
ischial spines (i.e. the plane of least
dimension), it is possible to deliver
vaginally.
• VIA: Four types of female pelvis: arthopoid
(narrow transverse, wide AP), gynecoid
(wide inlet & outlet), platypoidal (narrow
AP, wide transverse) and android
(loveheart shaped, narrow inlet & outlet).

5. Power
• Normal = 3 to 5 contractions per 10 minutes
• If less, there is slower cervical dilatation.
• If more, there is uterine hyperstimulation – this is associated with
foetal distress.

6. Passenger
• Lie: Relationship of the long axis of the foetus to the long axis of
the mother. [transverse/ longitudinal/ oblique]
• Presentation: The foetal pole that lies over the pelvic inlet.
[cephalic/ breech/ shoulder]
• Attitude: Relation of the foetal head to the spine. [flexed/
extended/ neutral]
• Denominator: Fixed bony point on presenting part that describes
the position
• Position: Relationship of the presenting part to the maternal bony
pelvis

7. Question time!
•What is labour?
•When is labour considered ‘at term’?
•What are the variables of labour?

8. Question time!
•What is labour?
Natural process that culminates in the delivery of one or
more infants. Retrospective diagnosis.
•When is labour considered ‘at term’?
Spontaneous delivery between 37-42 weeks.
•What are the variables of labour?
Passage: Maternal bony pelvis
Power: Uterine contractions (3-5)
Passenger: Foetus

9. Question time!
•Define foetal lie
•Define foetal presentation
•Define foetal position

10. Question time!
•Define foetal lie
Relationship of the long axis of the foetus to that of the
mother. May be longitudinal, transverse or oblique.
•Define foetal presentation
The foetal pole that lies over the pelvic inlet. May be
cephalic, breech or shoulder.
•Define foetal position
The relationship of the presenting part to the maternal bony
pelvis (e.g OA, OP)

11. Stages of labour

12. First stage
• Onset of labour to full cervical dilatation
• *** What does cervical dilatation mean?
• Two stages:
• Latent phase (~8H): Point at which woman perceives regular uterine
contractions until 4cm dilatation. Prolonged if >20H in a nullipara; >16H if
multipara.
• Active phase (~8H nullipara, 6H multipara): 4cm dilatation to fully dilated
and regular contractions. Rate of dilatation should be >1cm per hour if
nullipara; >1.5cm per hour if multipara.

13. Second stage
• Full dilatation to delivery of the baby
• Prolonged if >2H in a nullipara and >1H in a multipara. Add 1H if
epidural anasthesia is used.
• Phases:
• 1: Passive descent of head until levator ani is reached
• 2: Phase of active pushing.

14. Third Stage
• Delivery of the placenta and membranes.
• Normally 5-30 minutes. Prolonged if >1H.
• Expectant management of post-partum haemorrhage:
• 10IU of IM syntocinon as the anterior shoulder of the baby is delivered.
• Early cord clamping and cutting.
• Controlled cord traction.
• Fundal massage of uterus.
WARNING:
Placenta is the weirdest thing you will ever see!

15. •When is labour considered ‘at term’?
•What are the variables of labour?
•What are the stages of labour?
•What is expectant management of PPH?

16. •When is labour considered ‘at term’?
Spontaneous delivery between 37-42 weeks.
•What are the variables of labour?
Passage: Maternal bony pelvis
Power: Uterine contractions (3-5)
Passenger: Foetus
•What are the stages of labour?
First stage: Onset of labour to full cervical dilatation. Latent phase
(regular uterine contractions until 4cm dilatation) and active phase (4cm
to full dilatation. 1cm/hour if nulliparous, 1.5 if multiparous.
Second stage: Full dilatation to delivery of baby. Phase 1 (passive descent)
and phase 2 (active pushing). Prolonged if >2H nulliparous, >1H multipara.
Third stage: Delivery of placenta and membranes.
•What is expectant management of PPH?
10IU IM syntocinon as the anterior shoulder is delivered
Early cord clamping and cutting
Controlled cord traction
Fundal massage of uterus

17. Typical Vertex Delivery
• Descent: Head descends into pelvis
• Engagement: Widest part of head has passed below the pelvic inlet
with the head in transverse position.
• Flexion: Head flexes as it descends below the sacral promontory.
• Internal rotation: Head rotates into AP position.
• Extension: Inferior border of the symphysis pubis acts as a fulcrum
around which the foetal head extends.
• Restitution: Head rotates back into transverse plane

18. Delivery Stages

19. Vaginal Exam in Labour
• Used to assess cervical dilatation, membranes, station and
presenting part of foetus.
• Station: Number of cm of the presenting part past the ischial
spines. 0 station is at spines, negative numbers are above and
positive numbers below.
• Membranes: Intact will feel slippery, broken will feel rough.
• In a well flexed head, only the triangle shaped fontanelle should be
felt.

20. Question time!
•What are the variables of labour?
•What are the stages of labour?
•What are the variables of labour?
•Name four uses for a vaginal exam in labour.

21. Question time!
•What are the variables of labour?
Passage: Maternal bony pelvis
Power: Uterine contractions (3-5)
Passenger: Foetus
•What are the stages of labour?
First stage: Onset of labour to full cervical dilatation. Latent & active
Second stage: Full dilatation to delivery of baby. Phase 1 (passive
descent) and phase 2 (active pushing).
Third stage: Delivery of placenta and membranes.
•What are the variables of labour?
Descent
Engagement
Flexion
Internal rotation
Extension
Restitution
•Name four uses for a vaginal exam in labour.
Cervical dilatation
Membranes
Station
Presenting part