Normal Labour and Delivery

Question 1

How does parturition commence?

Answer 1

Fetal stress stimulates adrenocorticotropic hormone (acth) by the anterior pituitary which stimulates cortisol release from the adrenal glands

Question 2

What is the effect of cortisol release in partuition?

Answer 2

Affects the placenta

• decreases progesterone production
• decreases oestrogen production
• increases prostaglandin production - prostaglandin causes uterine contraction

Question 3

What is the Ferguson reflex?

Answer 3

Prostaglandin causes uterine contractions
Fetus causes stretching of uterus and cervix, stimulating sensory nerve fibres
Sensory nerve fibres stimulate oxytocin production from hypothalamus
Oxytocin stored in posterior pituitary is released, stimulating the release of prostaglandin and causes uterine contractions

Question 4

What are the two phases in stage I of pregnancy

Answer 4

Latent - initial

Active

Question 5

What happens in the latent phase of pregnancy?

Answer 5

Prostaglandin and Oxytocin release:
Uterine contractions

Effacement of cervix (thinning)

Question 6

When does the latent phase become the active phase?

Answer 6

When the cervix is dilated 3cm
Cervix continues to dilate (up to 10cm - crowning)
Contractions become more regular and more painful

Question 7

What is Stage II of labour

Answer 7

From 10cm dilatation to delivery of baby

Question 8

What is Stage III of labour?

Active management of Stage III

Answer 8

Delivery of placenta

Cutting of the umbilical cord
Controlled cord traction
Oxytocin IM

Question 9

What is the “show”?

Answer 9

Clear mucoid like discharge indicating labour is about to occur

Question 10

What physiological changes occur to make a woman’s water break?

Answer 10

Regular painful contractions
Increased intrauterine pressure
Amniotic sac rupture/ Spontaneous rupture of membranes

Clear - normal
Green/malodorous - meconium (can cause meconium aspiration)

Question 11

What happens if amniotic sack doesn’t spontaneously rupture?

Answer 11

Can perform amniotomy - induces/accelerates labour

Contraindicated in breech pregnancies and placental praevia

Question 12

How is failure to progress defined in nulliparous women?

Answer 12

Intial phase >20 hours

Active phase <1.2cm/hr dilation

Question 13

How is failure to progress defined in multiparous women?

Answer 13

Initial phase >14 hours

Active phase <1.5cm/hr dilation

Question 14

What are the differences between male and female pelvis?

Answer 14

Male
Shape - heart shaped, narrow
Coccyx - curved inwards
Pubic arch <90°
Iliac crest -more narrow, femur articulation more direct

Female 
Shape - oval
Coccyx - straight
Pubic arch >90°
Iliac crest - more flared, articulation with femur more lateral

Question 15

What are the 3 signs of placental separation

Answer 15

Uterus is well contracted

Cord has lengthened

Small trickle of blood

Question 16

How is postpartum haemorrhage defined?

Answer 16

Loss of >500mls blood after vaginal delivery
Loss of >1000mls blood after c section

Consider decrease of >10% haematocrit
Consider Mother’s BP, pulse, o2 sats

Within 24 hours = Primary (80% uterine atony)
>24 hours = Secondary

Question 17

Causes of postpartum haemorrhage

Answer 17

Tone (uterine atony - soft, spongy, boggy uterus)
Trauma (to uterus, cervix, vagina, perimeum)
Tissue (placental fragments retained in uterine cavity)
Thrombin (Von Willebrands, eclampsia, placental abruption - can lead to disseminated intravascular coagulation

Question 18

Causes of uterine atony

Answer 18

Repeated distention - multiple pregnancies, overstretching from twins
Muscle fatigue from prolonged labour
When in bladder retention
Iatrogenic - halothane, magnesium sulfate, nifedipine, terbutaline

Question 19

Treatment of uterine atony

Answer 19

Fundal massage causes uterine muscles to contract/harden

Urination/catheterisation

Medications

Surgery

Question 20

Treatment of postpartum haemorrhage causing trauma

Answer 20

Resuscitate
Identify cause
Site should be repaired asap
Remove retained products (unless adherent)
Give uterotonic drugs
Hysterectomy when bleeding cannot be stopped or accreta

Question 21

What is placenta acreta?

Answer 21

Placenta invades myometrium
Doesn’t easily separate from uterus

Prevents contractions and leads to uterine atony

Question 22

If PPH is suspected, when should a woman start breast feeding?

Answer 22

Immediately suckling action during breast feeding leads to the secretion of oxytocin from posterior pituitary

Question 23

What is the order of cardinal movements of labour?

Answer 23

Engagement
Descent
Flexion 
Internal rotation
Extension
External rotation 
Expulsion

Question 24

What is puerperium?

Answer 24

Period of ~6weeks after childbirth during which the mother’s reproductive organs return to non-pregnant condition

Question 25

What is the Kleihauer test?

Answer 25

Blood test to measure the amount of fetal haemoglobin transferred from a fetus to a mother’s bloodstream

Question 26

Risk factors for PPH

Answer 26

Multiple pregnancies - Grand multiparty  ≥5
Fibroids
Polyhydramnios
Placenta praevia
Maternl obesity 
Pre-eclampsia

Question 27

What is retained placenta?

Answer 27

Failure to deliver placenta within 30 minutes of the foetus (adherent or trapped behind closed cervix)

Prevents uterus from being able to contract down completely

Question 28

What are the cardinal movements of labour? (7)

Answer 28

Engagement

Descent

Flexion

Internal Rotation

Extension

Restitution and external rotation

Expulsion