Normal Labour

Question 1

Define normal labour?

Answer 1

Spontaneous labour at term (37-42 weeks) with fetus in vertex position resulting in a Spontaneous Vaginal Birth (SVD)

Question 2

What physiological changes must occur for labour to initiate? [3]

Answer 2

• Cervix softens
• Myometrial tone changes to allow for coordinated contractions
• Progesterone decreases while Oxytocin + Prostaglandins increase

Question 3

There are 3 stages of labour
What are the parts of Stage
1 of labour? [2]

Answer 3

Latent first stage

Established first stage

Question 4

What occurs during the latent first stage of labour?
Phase from full cervical dilation to birth of baby.
What occurs during the Established first stage of labour?
Duration in primi and multigravida? Rate?

Answer 4

Intermittent painful contractions leading to up to 4cm of dilatation

Regular Painful contraction producing progressive cervical effacement and 10cm dilatation.
Established first stage lasts an average 8 hours primagravida and 5 multigravida. Progresses at 0.5-1cm per hour

Question 5

The second stage of labour has 2 stages:
What occurs in the Passive 2nd stage of labour?
NB Allow 1 hour for the fetus to descend

Answer 5

This is the stage after your fully dilated but before Involuntary Expulsive Contractions occur

Question 6

What occurs in the Active Second stage of Labour? [3]

Answer 6

Expulsive contractions with full dilatation. The presenting part of fetus is visible and active maternal effort is required

Question 7

How long does the Active second stage of labour take?

Answer 7

Average 2 hours for primagravida and 1 for multigravida

Question 8

What occurs during the 3rd stage of labour?

Answer 8

Expulsion of the placenta and membranes

Question 9

What are the different ways we can handle the 3rd stage of labour?

Answer 9

• Active Management

- Physiological management - only admissible to women who are low risk for PPH or placental delivery complications

Question 10

Whats involved in Active management of the 3rd stage? [3]

What is prolonged third stage [2]

Answer 10

• Uterotonic drugs
• Deferred (2-5 mins) clamping and cutting of cord
• Delivery of placenta by controlled cord traction

Prolonged Third Stage is a diagnosis made after 30 minutes of active management or 60 minutes of physiological management

Question 11

We use a partogram once established labour has been confirmed to monitor the labours progress. What tests/measurements would this include other than evaluating ‘external signs’ [6]

Answer 11

• Abdominal Palpation, palpate uterine contractions
• Vaginal Exam
• Monitoring colour, smell and volume of liquor
• Fetal Heart rate
• Vital signs: BP/Pulse/Temp/RR/O2Sat/Urine output/Urinalysis

Question 12

What does abdominal palpation tell us about the labour? [6]

Answer 12

Fetal Lie
Presentation
Attitude
Denominator
Position
Engagement

Question 13

Define Fetal Lie and what are the 3 possibilities

Define Fetal Presentation [1]

Answer 13

Axis of foetus to mother.
Either Longitudinal (same axis as mom) or transverse (lying sideways) or Oblique

The part of the foetus that is foremost in the birth canal

Question 14

Define Fetal Attitude [1] and give examples [5]

Define fetal engagement

Answer 14

Foetus’s posture
i.e. back concave, straight or convex and head tilted forward or back

Degree to which the baby’s presenting part (head in vertex) has entered the pelvic inlet

Question 15

Define Fetal Position
What is it determined by [1]
What are the 2 factors that influence it?

Answer 15

Orientation of the foetus. Determined by which way the occiput (post fontanelle) is facing.

1) anterior vs posterior vs transverse
2) and left vs right

Question 16

What can be discerned on vaginal exam during labour? [3]

Answer 16

Fotal presentation, engagement & position

Cervical effacement and dilatation

Presence/absence of membranes

Question 17

How do we auscultate the foetal heart? [3]

How often should be auscultate the foetal heart if doing it intermittently? [2]

Answer 17

Intermittently with hand held doppler or Pinard

OR Continuously with Cardiotocograph (CTG)

Every 15 minutes in first stage and every 5 minutes in 2nd stage

Question 18

What do you look for when palpating uterine contractions? [2]

Answer 18

3-4 every 10 minutes lasting 40-60s each

Strength: moderate to strong not weak

Question 19

What are some external signs of labour? [2]

Answer 19

Rhomboid of Michaelis

Anal Cleft line

Question 20

What are the parts of the actual mechanism of labour? [7]

Answer 20

Descent
Flexion (of head)
Internal rotation of head (so facing downward)
Crowning and extension of head
Internal rotation of shoulders
External rotation of head
Lateral flexion to deliver shoulders

Question 21

What forms of analgesia can women get during labour? [7]

Answer 21

• Breathing and massage
• TENS
• Paracetamol and Dihydrocodeine
• Entonox
• Epidural
• Remifentanil as Patient controlled Analgesia

Question 22

What is entonox?

Answer 22

Inhalation Nitrous Oxide and oxygen

Aka gas and air

Question 23

Partogram
What is its importance? [2]
Other information recorded down [6]

Answer 23

Records progress of cervical dilation and descent of head
Enables recognition of a labour that is non-progressive
- Frequency, duration of contractions
- FHR
- Colour of liquor
- Caput and moulding
- Station/descent of the head
- Maternal heart rate, BP, temp

Question 24

What are indicators of fetal hypoxia? [2]

Answer 24

Changes in fetal heart rate

Passage of new meconium-stained liquor

Question 25

Indications for CTG NICE guidelines [5]

Answer 25

As per NICE guidelines; the following would warrant continuous CTG monitoring if any of the following are present or arise during labour;

• suspected chorioamnionitis or sepsis, or a temperature of 38°C or above
• severe hypertension 160/110 mmHg or above
• oxytocin use
• the presence of significant meconium
• fresh vaginal bleeding that develops in labour - this was a new point added to the guidelines in 2014

Question 26

What are the 2 components of interpreting CTGs?

Answer 26

Basal heart rate
- FHR 110-160 bpm
Baseline variability
- Normally varies between 5-25bpm

Question 27

What is baseline variability? [3]
Reduced variability causes [4]
What is a red flag level of variability?

Answer 27

• Baseline variability is a record of oscillations in heart rate around baseline
• Due to the millisecond-to-millisecond reactions of the sympathetic and parasympathetic activity on the heart
• Reflects integrity of the ANS

Reduced variability:

• Fetal sleep phase
• Hypoxia, infection and medication

<5 bpm variability = fetus in jeopardy

Question 28

Transient changes in FHR
Accelerations - clinical significance [2]
Decelerations classified into [3]

Answer 28

Accelerations: reflection of activity of somatic nervous system > reassuring sign of good fetal health

Decelerations
- Early, late, variable

Question 29

Early Decelerations of FHR
Pattern [3]
Ax
Timing

Answer 29

• Synchronous with uterine contractions
• Nadir occurs at peak of contraction
• Decrease in heart rate <40 bpm
  Ax: head compression, considered physiological
  Timing: seen in late first and second stage labour

Question 30

Late Decelerations of FHR
Pattern [2]
Ax [2]

Answer 30

• Onset of slowing HR occurs well after contractions
• Doesn’t return to normal baseline until at least 20s after contraction completed
  Ax: placental insufficiency, may indicate fetal hypoxia

Question 31

What are methods of fetal monitoring? [4]

Answer 31

Intermittent auscultation
CTG
Fetal electrocardiogram
Fetal acid-base balance = Fetal scalp blood sampling

Question 32

Fetal acid-base balance

Answer 32

Obtained from scalp through amnioscope
Position: left lateral to avoid risk of supine hypotension
Sample analysed in blood gas analyzer