Labour

Question 1

What is the definition of labour?

Answer 1

Regular uterine contractions associated with cervical effacement and dilatation and descent of the presenting part, with or without a “show” or ruptured membranes

Question 2

Describe how you would examine a woman in labour

Answer 2

Firstly I would assess the abdomen. Fundal height, fetal lie, presenting part and comment on the engagement. I would assess contractions by feeling the uterus, noting the duration and frequency.
Next I would examine the vulva and vagina. Working out to in I would assess for prolapse, vaginal stricture, and discharge. Next the cervix is assessed for effacement and dilation. Check for ruptured membranes, including quantity and colour. Lastly check the presenting part.

Question 3

What are the phases of labour?

Answer 3

The first stage of labour is divided into 3 phases
Latent phase: contractions and cervical dilation of up to 3cm. Can take 10-12 hours.

Accelatory phase: Cervix starts to dilate 1cm per hour and baby’s head descends

Transition phase: expulsion of the baby’s head

Question 4

What is the mechanism of labour?

Answer 4

Descent: L/R occipitotransverse p
Engagement: L/R occipitotransverse p (widest part of fetal head through widest part of the pelvis)
Flexion: suboccipitobregmantic becomes presenting part (does not occur in OP)
Internal rotation: OA (slope of pelvic floor causes 90 degree rotation)
Crowning: OA (when widest part of fetal head has navigated narrowest part of pelvis)
Extension: OA (occiput slips beneath suprapubic arch)
Restitution and External rotation: occipitotransverse (head moves into same plane as shoulders)
Shoulders move from transverse to anterior posterior position
Delivery of anterior shoulder (downward traction)
Delivery of posterior shoulder (upward traction)

Question 5

What are the common causes of slow progress in labour?

Answer 5

Small pelvis
Large baby
OP presentation
Inefficient contractions

Question 6

How can we manage slow progress?

Answer 6

IV fluids, pain relief and reassurance
Amniotomy
Oxytocin
Caesarean

Question 7

Why are some babies OP?

Answer 7

Can be due to flat sacrum, poorly flexed head or weak uterine contractions

Question 8

How do you tell the difference between the anterior and posterior of the baby’s head?

Answer 8

Posterior fontanelle (3 radiating sutures)
Anterior fontanelle (4 sutures)

Question 9

How can you tell on abdominal examination if a baby is OP?

Answer 9

You can feel a concavity instead of the roundness of the baby’s back. The mother may also be experiencing back labour.

Question 10

Why is OP inherently more likely to cause a tear than OA?

Answer 10

OP means the baby’s head is 11cm

OA means the baby’s head is 9.5cm

Question 11

How do we manage OP?

Answer 11

1/3 will deliver vaginally
1/3 will turn into OA
1/3 will transverse arrest
Instrumental delivery or caesarean is likely

Question 12

What are the biggest risk factors for shoulder dystocia?

Answer 12

Obesity
LGA
Diabetes

Question 13

How do we manage shoulder dystocia?

Answer 13

Check that baby is stuck on pelvic inlet
Apply downwards traction
Apply suprapubic pressure
McRoberts manouvre

Question 14

What are the different types of deceleration?

Answer 14

Early: normal in first stage. HR at lowest point at peak of contraction. Indicate fetal head compression

Late: lowest Hr measured 15 secs after contraction. Associated with hypoxia

Variable: inconsistent, caused by cord compression which may lead to hypoxia

Question 15

When the fetus flexes her head, which part of the skull do you see?

Answer 15

Suboccipitobregmatic diameter (narrowest part)

Question 16

How do we monitor a woman in labour?

Answer 16

Depends on stage and risk factors.
Stage one: maternal vital signs plus urinalysis hourly
Fetal heart rate every 15 minutes
Vaginal exam using Bishop score
Stage 2: maternal vital signs every 1/2 hour
Fetal heart rate monitored every 5 minutes or constantly
Vaginal exam for crowning

Question 17

What is active management of the third stage of labour?

Answer 17

Ecbolic injection given at time fetal shoulder is delivered
Clamp the umbilical cord early
Press on the abdomen with controlled cord traction
Examine the placenta to ensure it is complete

Question 18

What is the Bishop’s score?

Answer 18

C onsistency of cervix (firm, interm, soft)
P osition of cervix (posterior, interm, anterior)
E ffacement (measure of stretch of the cervix)
D iameter of cervix
S tation (if negative, baby's head is above ischial spines, if positive, below ischial spines)