Physiology of 2nd Stage Flashcards Preview

Scientific Basis of Midwifery > Physiology of 2nd Stage > Flashcards

Flashcards in Physiology of 2nd Stage Deck (15)
Loading flashcards...
1
Q

Describe the 2nd stage of labour

A
  • Full dilation to birth
  • Strong contractions every 2-3 minutes lasting 1 minute
  • Foetus descends down birth canal
2
Q

Name some of the features of the second stage of labour

A
  • Increase contraction intensity
  • Membrane rupture?
  • Pressure of foetal head on sacral/ obsturator nerve
  • Increased perspiration
  • Stretch receptors stimulated
  • Anus everted and patulous (open and spread out)
  • Bulging of perineal region
  • Dilated and distended vulva
  • Rapid contractions with no interval
  • Crowning
  • Delivery
3
Q

What are the primary and secondary powers?

A

Primary power = involuntary (contraction, retraction, relaxation)
Secondary power = urge to push

4
Q

Describe crowning

A

Vulva stretches and encircles the largest diameter of the foetal head

5
Q

What can delay labour?

A

Full bladder

6
Q

What cardiovascular changes occur in the mother during 2nd stage?

A
  • CO 40-50% up to 100%
  • Compression of aorta and iliac arteries
  • CO shifts to head and upper extremities
  • BP increases by 30/25mmHg (during contraction) or 10/5mmHg (between contractions)
  • Steady increase in PR to 100bpm
7
Q

Why does cardiac output increase?

A

Increase in catecholamines resulting from pain

8
Q

Give some reasons that pulse rate may increase

A
  • Dehydration
  • Anxiety
  • Pain
  • Some drugs
9
Q

What is the most accurate period of assessment for vital signs?

A

Between contractions

10
Q

What respiratory changes occur in the mother during 2nd stage?

A
  • Increase in metabolism increases oxygen demand = increased RR
  • PP of carbon dioxide decreases (32mmHg to 22mmHg)
  • Hyperventilation common - leads to decreased PP of carbon dioxide
  • Opposite effect occurs in excessive shallow breathing
  • Excessive/prolonged maternal pushing causes decrease in oxygen
11
Q

What gastrointestinal changes occur in the mother during 2nd stage?

A
  • Decreased motility and absorption in active phase
  • Delayed emptying time
  • Exaggerated after narcotic intake
  • Nausea and vomiting
  • Dehydration, dry lips and mouth due to breathing deeply
12
Q

What renal changes occur in the mother during 2nd stage?

A
  • Full bladder may be masked by intensity of contractions and pressure of presenting parts
  • May cause delayed progress/ trauma
  • Diaphoresis (excessive sweating)
  • Increased water loss through perspiration
13
Q

What haematopoietic changes occur in the mother during 2nd stage?

A
  • 500ml (usual loss)
  • 1000ml (lost in CS)
  • Compensated by hypervolemia
  • Slight decrease in coagulation time
  • Increased plasma fibrinogen levels
  • Decreased leucocyte levels as labour progresses
14
Q

What fluid and electrolyte changes occur in the mother during 2nd stage?

A
  • Decrease in plasma Na and Cl levels due to decreased GI tract absorption, panting and diaphoresis
  • Polyuria is common
  • Analgesia may affect foetal electrolyte balance
15
Q

What should be monitored in 2nd stage?

A
  • Uterine contractions
  • Cervical dilation
  • Descent of presenting part
  • Maternal wellbeing
  • Foetal wellbeing