Normal Labour

Question 1

What is normal labour?

Answer 1

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

Question 2

How is the initiation of labour triggered?

Answer 2

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

Question 3

What are the stages of labour?

Answer 3

Stage I- split into latent and established
Stage II- active and passive
Stage III

Question 4

What processes occur during the latent first stage of labour?

Answer 4

The latent stage involves contractions that are irregular and short, and not usually painful at this point

Question 5

What is involved in the established first stage of labour?

Answer 5

Established labour involves regular, painful contractions with varying lengths

Question 6

When is the first stage of labour complete?

Answer 6

When the cervix is fully dilated at 10cm, with normal progress being 0.5-1.0cm per hour.

Question 7

Between what processes is the second stage of labour?

Answer 7

Stage II of labour occurs between full dilatation of the cervix and the birth of the baby

Question 8

What is the passive second stage of labour?

Answer 8

The passive stage is when the cervix is fully dilated but there are not yet any involuntary expulsive contractions

Question 9

What is the active second stage of labour?

Answer 9

The active stage is when the presenting part is visible and there are involuntary expulsive contractions

Question 10

How long after initiation of the active second stage of labour would birth be expected?

Answer 10

Primigravida- within two hours

Multigravida- within one hour

Question 11

How long should the passive second stage of labour last?

Answer 11

The passive stage should be allowed to last for up to two hours before active maternal effort is started

Question 12

Between what processes is the third stage of labour?

Answer 12

Stage III of labour occurs between the birth of the baby and the expulsion of the placenta and membranes

Question 13

How long should the third stage of labour last?

Answer 13

Considered to be prolonged if not complete within 30 mins of birth with active management or 60 mins with physiological management

Question 14

What active management can be given for stage III of labour?

Answer 14

Uterotonic drugs
Optimal cord clamping
Controlled cord traction

Question 15

What passive management is involved in stage III of labour?

Answer 15

Delivery of placenta by maternal effort
Cord clamped once pulsation has stopped
No uterotonic drugs

Question 16

What are the possible methods for monitoring progress of labour?

Answer 16

• 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)

Question 17

How is CTG monitoring done and why is it helpful?

Answer 17

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.

Question 18

What processes are involved in the mechanism of labour?

Answer 18

• 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

Question 19

What are the features of normal labour?

Answer 19

Longitudinal lie
Attitude of good flexion
Cephalic presentation
LOA or ROA position
Denominator is occiput
Presenting part is anterior parietal bone

Question 20

How is crowning defined?

Answer 20

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.

Question 21

What analgesia can be given during labour?

Answer 21

• 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