Kate Charters

WHERE DO BABIES COME FROM?

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.

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

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).

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.

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

Question time!

•What is labour?

•When is labour considered ‘at term’?

•What are the variables of labour?

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

Question time!

•Define foetal lie

•Define foetal presentation

•Define foetal position

Question time!

•Define foetal lieRelationship of the long axis of the foetus to that of the mother. May be longitudinal, transverse or oblique.

•Define foetal presentationThe foetal pole that lies over the pelvic inlet. May be cephalic, breech or shoulder.

•Define foetal positionThe relationship of the presenting part to the maternal bony pelvis (e.g OA, OP)

Stages of labour

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.

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.

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!

•When is labour considered ‘at term’?

•What are the variables of labour?

•What are the stages of labour?

•What is expectant management of PPH?

•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

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

Delivery Stages

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.

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.

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