Labour

Question 1

What is parturition?

Answer 1

Transition from pregnant to non-pregnant state

Question 2

What is labour?

Answer 2

Process by which a foetus is expelled from the uterus to the outside world

Question 3

What is delivery?

Answer 3

Method of expulsion of the foetus

Question 4

What are the purposes of contractions?

Answer 4

Dilation of the cervix

Pushing the foetus through the birth canal

Question 5

How many stages of labour are there?

Answer 5

3

Question 6

What is the first stage labour?

Answer 6

Creation of the birth canal

Question 7

What is the clinical definition of the first stage of labour?

Answer 7

Interval between the onset of labour and full dilatation of the cervix

Question 8

How is the first stage of labour divided?

Answer 8

Latent phase

Active phase

Question 9

What is the latent phase?

Answer 9

Onset of labour with slow cervical dilation

Question 10

What is the active phase?

Answer 10

Faster rate of change and regular contractions

Question 11

What is the second stage of labour?

Answer 11

Delivery of foetus

Question 12

What is the clinical definition of the second stage of labour?

Answer 12

Time between full dilatation of the cervix and delivery of the foetus

Question 13

What are the 2 parts of the second stage of labour?

Answer 13

Passive

Active

Question 14

What is passive labour?

Answer 14

Descent and rotation of the head

Question 15

What is active labour?

Answer 15

Maternal effort to expel the foetus and achieve birth

Question 16

What is the third stage of labour?

Answer 16

Expulsion of the placenta

Question 17

What is the clinical definition of the third stage of labour?

Answer 17

Time between completed delivery of the baby and completed delivery of the placenta

Question 18

How is labour initiated?

Answer 18

Prostaglandins promote cervix ripening

Increase in contractility of myometrium

• increase in prostaglandins - increase calcium release
• increase in oxytocin - lowers threshold for action potentials

Initiates uterine contractions

Question 19

What is cervix ripening?

Answer 19

Reduction in collagen
Increase in glycosaminoglycans
Increase in hyaluronic acid

Question 20

What is the effect of progesterone on labour?

Answer 20

Progesterone inhibits contractions

Question 21

What is the effect of oestrogen on labour?

Answer 21

Increases gap junctional communication between smooth muscle cells - increases contractility

Question 22

What are the borders of the birth canal?

Answer 22

Posterior = sacral promontory 
Lateral = ilio-pectineal line 
Anterior = superior pubic rami

Question 23

What is special about the myometrium?

Answer 23

When they contract, they only partially relax so there is permanent shortening of the fibres

Forces foetus out of uterus

Question 24

What controls contractility?

Answer 24

Prostaglandins
- more Ca2+ per action potential

Oxytocin

• more action potentials
• lowers threshold

Question 25

What are the common foetal presentation descriptors?

Answer 25

Lie Attitude Presentation

Question 26

What is lie?

Answer 26

Relationship of long axis of foetus + uterus

Question 27

What are the different lie positions?

Answer 27

Longitudinal = foetus in position ready for birth Transverse = foetus perpendicular to uterus

Question 28

What is attitude?

Answer 28

Posture of foetus during labour

Question 29

What is the normal attitude position?

Answer 29

Flexed

Question 30

What is foetal presentation?

Answer 30

Which part of the body is adjacent to the pelvic inlet

Question 31

What is the normal foetal presentation?

Answer 31

Head is first

Question 32

What is breech presentation?

Answer 32

Any other part is nearest pelvic inlet - commonly legs/bum

Question 33

How can labour be stimulated?

Answer 33

Membrane rupture - stimulates prostaglandin release Artificial prostaglandins Synthetic oxytocin Anti-progesterone agents

Question 34

How can foetus physiology be monitored during birth?

Answer 34

Foetus monitoring - heart rate - movements Maternal temp Colour + amount of amniotic fluid Scalp capillary pH

Question 35

What is the normal mechanism of labour?

Answer 35

``` Foetus head flexes Head rotates internallu Crowning = head stretches the muscle + skin Head extended + externally rotates Shoulders rotate Delivery ```

Question 36

How can delivery be assisted?

Answer 36

Instruments - forceps - vacuum Caesarean section

Question 37

What is the risk of instrument delivery?

Answer 37

Nerve palsy - Erb's palsy - Klumpke palsy

Question 38

What is Erb's palsy?

Answer 38

Damage to upper part of brachial plexus (C5-7) ``` Elbow = extended Forearm = medially rotated + pronated Wrist = weakly flexed ```

Question 39

What is Klumpke palsy?

Answer 39

Damage to lower part of brachial plexus (C8-T1) ``` Elbow = extended Forearm = supinated Wrist = flexed ```

Question 40

How is the placenta delivered?

Answer 40

Placenta separated by uterine contractions Powerful contraction - constrict the blood vessels Blood clotting mechanism activated

Question 41

What stimulates the neonates first breath?

Answer 41

Trauma Cold Light Noise

Question 42

What is the effect of the first breath?

Answer 42

Tissue resistance decreases in lungs Vascular resistance increases - blood flows to lungs Blood becomes oxygenated - pulmonary pO2 increases Drop in pressure in RA - foramen ovale closes Increased pO2 causes muscle walls to contract - ductus arteriosus closes

Question 43

What causes the ductus venosus to close?

Answer 43

Clamping the umbilical cord