Normal labour and its management

Question 1

What is the common cause of death in childbirth?

Answer 1

Severe bleeding
Infection
Pre-eclampsia

Question 2

What is an intrapartum stillbirth?

Answer 2

Foetal death after onset of labour due to inadequate foetal heart rate monitoring measured on a partogram.

Question 3

How does onset of labour occur?

Answer 3

Forces of release overcome forces of retention

Question 4

What promotes retention of baby in labour?

Answer 4

Progesterone inhibits uterine contractions

Adrenaline causes sympathetic activation due to fear or pain slows labour and inhibits oxytocin.

Relaxin causes relaxation of the pelvic ligaments.

Question 5

What promotes release in labour?

Answer 5

Prostaglandins

Oxytocin and vasopressin stimulates uterine contractions.

Uterine distention to swells to prepare for head

Corticotropin releasing hormone and corticol.

Question 6

What is the role of prostaglandin in labour?

Answer 6

Induces labour by causing softening and stretching of the cervix.

Question 7

What is the role of cortisol in labour?

Answer 7

Responsible for maturation of foetal organs before labour and timing of birth

Question 8

What is the role of oxytocin in labour?

Answer 8

Oxytocin is triggered to be released due to stretching of the cervix by the foetal head. It causes uterine contractions, softening and dilation of the cervix and positive feedback for release of prostaglandins.

Question 9

What are the mechanisms of labour?

Answer 9

Passage
Power
Passenger

Question 10

What is passage in labour?

Answer 10

Movement of foetus through pelvis, spine and soft tissues of uterus, cervix, bladder and vagina.
There are 4 pelvic shapes: gynaecoid, android, anthropoid and platypelloid.

Question 11

What is the most common pelvic type?

Answer 11

Gynaecoid which has a wide open shape most ideal for delivery.

Question 12

How does the foetus interact with the pelvis during labour?

Answer 12

Engages with the pelvic inlet in a transverse position and rotates into a anterior-posterior position.

Question 13

What is the smallest part of the foetal skull?

Answer 13

Suboccipital bregmatic, which occurs when the foetal head is in a flexed position.

Question 14

What is power in labour?

Answer 14

Generated by contraction of the uterus myometrium via action of oxytocin and vasopressin hormones.

Question 15

Where do contractions begin in the uterus?

Answer 15

Fundal dominance where contractions begin and are strongest at the fundus. There should be a regular pattern to contractions unless labour has slowed down or baby is in awkward position.

They continue post-birth to return uterus to normal size.

Question 16

What is tone in labour?

Answer 16

Partial contraction of muscle to return it to resting state and help downward movement of foetus. This begins at 35 weeks and is the cause of Braxton Hicks

Question 17

What is normal rhythmicity in labour?

Answer 17

Rate of 4-10 per minute

Question 18

What is the passenger in labour?

Answer 18

Portion of the skull at the opening of the pelvis is the proportion that will descend

Question 19

What is the role of the skull fontanelles?

Answer 19

Allows for growth of the brain and skull during foetal development

Question 20

What is the size of the pelvic outlet?

Answer 20

11cm

Question 21

What is the average size of a foetal head?

Answer 21

9.5cm

Question 22

What can cause failure of labour in the passenger stage?

Answer 22

Cephalopelvic disproportion: mismatch between foetal head and pelvic size that causes the bones of the skull to compress and overlap

Question 23

What are the stages of labour?

Answer 23

Latent phase
1st stage
2nd stage
3rd stage

Question 24

What is the latent phase of labour?

Answer 24

Onset of contractions which become regular
3-4cm dilated cervix
Cervix effaced: softening, thinning and shortening of cervix to allow unobstructed passage of the head due to action of prostaglandins when the head presses on the cervix.

Question 25

What is cervical dilation?

Answer 25

Increase in diameter of the cervix opening. Requires effacement (softening) for dilation to occur via the action of oestrogen and progesterone.

Question 26

What is the first stage of labour?

Answer 26

Regular contractions, and fully dilated at 10cm. It is the longest stage of labour

Question 27

What is the second stage of labour?

Answer 27

Passive contractions of foetus into pelvis
Active pushing

Question 28

What are the cardinal movements?

Answer 28

Occur in the 2nd stage of labour with the movement of the foetus through the pelvis

1)Engagement in transverse position
2)Descent
3)Flexion of foetal head to create more space
4)Internal rotation of baby which pelvic floor muscles allow
5)Extension of head beneath the suprapubic arch via abdominal pressure. This causes stretching of the perineum.
6)External rotation of the head and the shoulders to an anterior-posterior position
7)Expulsion

Question 29

What is restitution?

Answer 29

Realignment of the shoulders of the foetus with the head to an anterior-posterior position.

Question 31

What is the third stage of labour?

Answer 31

Post birth with delivery of baby, placenta and membranes. At the interface between placenta and endometrium, large vascular connections for transfer of nutrients.

Question 32

What happens once the placenta is delivered?

Answer 32

Open vascular beds which can bleed torrentially.

Question 33

What affects labour time?

Answer 33

Primiparous: first birth which is shorter at all stages of labour
Multiparous: previous history of birth where labour is longer.

Question 34

What is a treatment for delayed labour?

Answer 34

Oxytocin and controlled cord contraction to apply pressure to uterus to promote uterine contraction and speed up third stage uterus.

Question 35

What causes post-partum haemorrhage?

Answer 35

Inability of the uterus muscles to contract around the blood vessels to prevent haemastasis. This can be prevented by controlled cord contractions and synthetic oxytocin to promote uterine contractions around the blood vessels for hameastasis.

Question 36

How is normal labour regulated?

Answer 36

Regulate bladder emptying, evaluation of maternal and foetal condition and evaluation of birth plan. Provide episiotomy and controlled head delivery.

Question 37

What is partogram?

Answer 37

Used to document the progress of labour via cervical dilation

Question 38

What are the analgesics of the labour?

Answer 38

Transcutaneous nerve stimulation
Opiates
Epidural
Oral analgesics

Question 39

What causes hypoxia in the foetus?

Answer 39

Overactivity of the uterine muscle activity or not enough muscle tone

Question 40

How is foetal wellbeing assessed?

Answer 40

Craniotopography to assess foetal heart rate and uterine muscle activity.

Question 41

What is normal resting newborn heart rate?

Answer 41

Considered tacychardic at above 160bpm. Variation is normal due to immature nervous sytem.

Question 42

What is the most common cause of direct maternal death?

Answer 42

Thromboembolism.

Question 43

What is the leading cause of maternal mortality?

Answer 43

Suicide
Post-partum haemorrhage

Question 44

What is the most common cause of indirect maternal death?

Answer 44

Cardiac disease

Question 45

What is the role of oestrogen in labour?

Answer 45

Levels decline gradually in the 2nd and 3rd trimester but it promotes the release of prostaglandins and expression of oxytocin receptors. There is a significant decrease after placenta delivery along with progesterone.

Question 46

What is a non-hormonal method to induce labour?

Answer 46

Using a cooked ballon which causes dilation of the cervix by creating a balloon of air near the baby’s head and at the cervix opening.