Normal Labour

Question 1

What is meant by the following terms:

1. Labour
2. Lie
3. Presentation
4. Position
5. Station
6. Attitude

Answer 1

1. Labour:
   
   • The process by which the foetus and placenta are expelled from the uterus.
2. Lie:
   
   • general position of where the baby is lying longitudinal/transverse/oblique
3. Presentation:
   
   • the lowest part of the fetus: cephalic, breached
4. Position:
   
   • Which way round the baby is facing OA or OP or OT (occipital anterior/posterior/transeverse)
5. Station:
   
   • How high is the baby’s head in relation to the ischial spine. Same level = 0 +ve = lower than ischial spine -ve = higher than ischial spine
6. Attitude:
   
   1. the degree the head is flexed, full flexion = vertex may also be brow (extended) or face (hyper extended)

Question 2

When doing a vaginal examination during labour what are the 5 things you should comment on?

Answer 2

1. Dilation of cervix
2. Station
3. Position of head (OA is best, OT/OP may need assisted delivery
4. Caput (baby head swelling due to reduced venous drainage due to pressure from cervix/pelvic inlet) -
5. Moulding (refers to the bones in the skull squeezing together to slightly reduce the size of the head, this is possible due to the fontanelles not being fused) Note: OT position is incompatible with an non assisted labour

Question 3

What are the 3 P’s factors which affect the course of labour?

Answer 3

1. Powers
   
   • ​​uterine contractions (frequency, intensity, duration)
   • degree of force expelling the fetus
2. Passenger
   
   • fetal position
   • the diameters of the fetal head
3. Passage
   
   • bony pelvis and soft tissue resistance different types of female pelvic shape (gynecoid is the most common)
   • The dimensions of the pelvis and the resistance of soft tissue

Question 4

What are the different planes and structures which need to be manoeuvred for passage of the fetus? (3 bony pelvis + soft tissue)

Answer 4

Pelvic Inlet:

• Transverse diameter is ~13cm
• Anterior posterior diameter is ~ 11cm

Mid-Pelvis:

• Ischial spines are palpable vaginally used to calculate fetus’s station

Outlet:

• Anterior - posterior ~ 12.5cm
• Transverse diameter ~ 11cm

Soft Tissue:

• Cervix softens and distends
• The soft tissues of the vagina and perineum need to be overcome in the 2nd stage. There perineum may tear or may be artificially cut (episiotomy) to aid delivery of the head.

Question 5

When is a women classed to be in labour and how this can be diagnosed?

Answer 5

When she is experiencing:

• regular, painful uterine contractions 3 in 10 mins which increase in frequency
• dilation and effacement of cervix
• Cervical effacement = thinning of the cervix
• Contractions usually last 45-60 sec and occur every 3 mins.
• Contractions can be assessed by:
  
  • Palpation
  • Pressure transducer on CTG (also known as a tonometer)
  • Intrauterine pressure catheter Cervical dilation and effacement is assessed with a VE

Question 6

What are the different stages of labour?

Answer 6

Stage 1: Initiation to full cervical dilation (10cm)

Stage 2: Starts at full cervical dilation to delivery of fetus

Stage 3: From delivery of fetus to delivery of placenta

Question 7

What is meant by the terms water’s breaking and show?

Answer 7

Water’s breaking refers to the membranous bag containing the fetus and the amniotic fluid being ruptured and the amniotic fluid rushing out.

Show refers to the mucus plug around your cervix coming away from the cervix and ‘showing’

Question 8

What are the functions of the amniotic fluid and mucus plug?

Answer 8

Both protect against fetal infection

Amniotic fluid also helps protect against trauma and infection.

Question 9

What should you be monitoring during labour?

Answer 9

• FHR every 15 mins or continuously with CTG.
• Contractions frequency and strength should be monitored.
• Maternal Observations hourly.
• VE 4 hourly.
• Urine dip for ketones, 4 hourly/when they pass urine.

Question 10

What are the potential causes for a poor progressing labour?

Answer 10

1. Powers: -Inaffective uterine contractions
2. Passage: -Small pelvis
3. Passenger: -Malposition, Malpresentation or large baby

Question 11

How do you manage a poorly progressing labour?

Answer 11

Review aka abdo exam, hydration status, analgesia, FHR, VE

If water’s have not broke:

• Artificial rupture of membranes using an amniotic hook
• Can give Syntocin infusion (oxytocin) needs CTG if this is being started. (needs senior review for this to be started if this is a multi para women).
• VE should be performed on a 2hourly basis.
• Consider a lower segment caesarean if not progressing after 12hours on syntocin drip or if there is fetal distress.

Question 12

How should you dose syntocin?

Answer 12

Start at 6mls/hr (4mU/min)

Increase in 30 min increments until there are regular contractions.

Max dose is 30mls/hr (20mU/min)

Question 13

What time span classes as a poorly progressing labour in stage 1?

Answer 13

Latent phase: Nulliparous >20hrs Multipara>14hrs

Lack of cervical dilation in active phase.

Approximately you should expect 1cm/hr dilation when in active phase for nulliparous woman and 2cm/hr in multiparous

Question 14

What time span classes as a poorly progressing labour in stage 2?

Answer 14

Nulliparous: Prolonged if >2hrs

Multipara: Prolonged if> 1hr

Note if woman has local anaesthesia 1 hr extra is allowed before it is classed as prolonged.

Question 15

Describe the normal path a fetus will take in stage 2?

Answer 15

1. Engagement: passage of the widest diameter of the head through the pelvic inlet. Foetus’s head is usually in OT position at this point (transverse diameter is greater than OA here).
2. Descent downward through the pelvis.
3. Flexion of the fetal head - vertex presentation (chin rests on chest) occurs passively due to the shape of the bony pelvis.
4. Internal Rotation: the fetus’s head rotates so that it is no longer OT but OA. This is occurs passively due to the shape the pelvis and the pelvic floor musculature.
5. Extension and delivery. The fetus is at the level of the introitus (the opening of the vaginal canal). The occiput is in contact with the pubic symphysis. A downward force is exerted on the foetus by the uterine contractions and an upward force is exerted by the pelvic floor muscles causing the fetal head to deliver by extension.
6. External rotation (restitution). The fetal head rotates 90 degrees so that it is facing in its original position.
7. Expulsion refers to the delivery of the rest of the body with anterior shoulder coming first.

Question 16

What are the different methods of assisted delivery?

Answer 16

Ventouse: Suction fetal head to assist delivery (not commonly used as can be associated with a vagal response and a fetal bradycardia)

Forceps: To help pull put the baby

Episiotomy: A diagonal surgical cut to the perineum to widen the ‘hole’ and make delivery of the head easier.

In normal deliveries the midwife’s hand is used to control delivery and prevent very fast delivery which is associated with perineal injury.

Question 17

What are the 3 clinical signs of uterine contraction?

Answer 17

1. A sudden rush of blood
2. Apparent lengthening of the umbilical cord
3. Elevation and contraction of the uterine fundus

Question 18

What is the physiological management of stage 3?

Answer 18

Allow chord to stop pulsating 2-3mins before clamping and cutting. Placenta is delivered by maternal effort alone.

Question 19

When should you consider active management of stage 3?

Answer 19

Should change to active management if there is large haemorrhage (normal is up to 500ml but would still want to intervene in this scenario)

Failure to deliver the placenta in 1hr. (infection risk) Maternal desire.

Question 20

What is classed as active management of stage 3?

Answer 20

Use of Syntometrine IM (ergometrine 0.5mg and oxytocin 5IU) (uterotonic)

Controlled chord traction is applied whilst supporting fundus. (Brandt Andrew technique)

Question 21

What are the advantages of an active stage 3?

Answer 21

Reduced risk of PPH >1000ml

Reduce risk of needing transfusion

Reduced risk of post part maternal anaemia

Decreased length of stage 3

Question 22

What are the potential complications post delivery (uptp 2hrs)?

Answer 22

Perineal tear immediately after delivery usually repaired immediately

PPH

Uterine inversion

Retained placenta

Question 23

What is uterine inversion?

Answer 23

Uterine inversion is a potentially fatal childbirth complication with a maternal survival rate of about 85%.

It occurs when the placenta fails to detach from the uterus as it exits, pulls on the inside surface, and turns the organ inside out. It is very rare.

Question 24

What is the APGAR score?

Answer 24

It is a score to assess a newborns initial health and is used at 1 5 and 10 mins post partum.

• Activity (muscle tone)
• Pulse
• Grimace (reflex irritability)
• Appearance (skin colour)
• Respiration
  
  • Score of 7 or greater = excellent condition
  • 4-6 = moderately depressed
  • 3 or less = severely depressed