Labour

Question 1

How is onset of labour defined?

Answer 1

Myometrial changes
Cervical changes
Hormonal changes
Interactions between the foetus and the above

Question 2

Explain the myomertial changes which precipitate labour?

Answer 2

1. Stretching of the myometrium increases muscle excitation and contractility
2. Gap junctions form due to oestrogen which enables a synchronised contraction wave
3. Horizontal myometrial bands are drawn upwards, thinning and dilating (effacing) the cervix
4. Vertical myometrial bands actively contract and shorten, pulling the uterus upwards

Question 3

Explain the cervical changes which precipitate labour

Answer 3

Decreases in collagen and increases in water content allow the cervix to soften, efface and dilate

Question 4

Explain the hormonal changes which precipitate labour

Answer 4

Increased oxygen levels stimulate prostaglandin release and promotes formation of oxytocin receptors, both of which are myometrial stimulatnts and encourage cervical ripening

Question 5

What is cervical ripening?

Answer 5

Dilation and effacement

Question 6

How does the foetus interact with the myometrium, cervix and hormones to precipitate labour?

Answer 6

Foetus pushes against cervix, causing it to stretch
This stimulates the pituitary to release oxytocin
Oxytocin makes the uterus contract

Question 7

What is the role of oxytocin in labour?

Answer 7

Causes contractions

Question 8

What are the phases of labour and their definitions?

Answer 8

Latent: painful contractions AND dilation up to 4cm
Established: regular painful contractions and dilation over 4cm

Question 9

What are the stages of established labour?

Answer 9

Stage 1: 4-10cm dilation
Stage 2: 10cm to birth of baby
Stage 3: birth of baby to delivery of placenta and membranes

Question 10

How can the second stage of labour be divided?

Answer 10

Active: urge to push and expulsive contractions
Passive: 10cm dilation with no urge to push

Question 11

What is the longest stage of labour?

Answer 11

First stage (4-10cm dilation)

Question 12

How can head descent be assessed?

Answer 12

On VE: ‘station’

Via abdominal exam using ability to feel head above pelvic brim

Question 13

Describe the station measurment for head descent

Answer 13

Head is above the ischial spines: station -1 to -4
Head is level with ischial spines: station 0
Head is below ishcial spines: station +1-+3

Question 14

Descibe the /5 measurements for head descent via abdominal examination

Answer 14

5/5 entire head palpable above pelvic brim
4/5: sinciput high, occiput easily felt
3/5: sinciiput easily felt, occiput felt
2/5: sinciput felt, occiput just felt
1/5: sinciput just felt, occiput not felt
0/5: none of head palpable

Question 15

What is the sinciput and occiput?

Answer 15

Occiput = back of baby's head
Sinciput = baby's forehead

Question 16

What advice can be given to women during the first stage of labour? What does this decrease the risk of?

Answer 16

Encourage mobility and remaining upright.

Decreases the risk of C-section and need for epidural

Question 17

What are the characteristics of a good second stage of labour?

Answer 17

Longitudinal lie
Good flexion (head tucked(
R or L occipitoanterior
Occiput is 1st part to enter the cervix

Question 18

Define prolonged second stage?

Answer 18

Nulliparous: 2+hrs of active pushing
Multiparous: 1+hrs of active pushing

Question 19

Describe the third stage of labour

Answer 19

The uterus continues to contract and and reduces in size
The placenta tetaches from the uterine wall and is passed
Following the placental detatch, the uterus clamps down - contracts and retracts, which compresses vessels and arrests bleeding

Question 20

Define prolonged third stage

Answer 20

30mins without passage of the placenta

Question 21

What is expectant management of the third stage?

Answer 21

Delivery of the placenta is by maternal effort without any uterotonic drugs
The cord is not clamped untul pulsation has ceased

Question 22

Describe the active management in the third stage of labour

Answer 22

Syntometrine to aid delivery of placenta
Delayed cord clamping
Controlled cord traction - applying counter pressure above the pubic bone and gentle downwards traction on the cord

Question 23

What is the different between syntocinon and syntometrine

Answer 23

Syntocinon: used to induce
Syntometrin: used to manage 3rd stage of labour