Physiology Of The Third Stage Of Labour

Question 1

What is the third stage of labour?

Answer 1

The third stage of labour is the time from the birth of the baby to the expulsion of the placenta and membranes

Question 2

What is delayed cord clamping?

Answer 2

Waiting before clamping the baby’s umbilical cord at birth. Waiting 1-5mins is recommended – NICE

Question 3

What is optimal cord clamping?

Answer 3

When the umbilical cord vessels are allowed to close naturally, until the cord stops pulsating and becomes white it is clamped and cut

Question 4

What is the physiological management?

Answer 4

• Do not administer a uterine tonic & do not cut and clamp the cord
• Await signs of separation: lengthening of cord, globular uterus, firm fundus on palpation and gush of blood vaginally (separation bleeding)
• Do not perform controlled cord traction
• Placenta will be birthed with support of maternal effort or gravity
• Usually completed within an hour of the birth of the baby
• Breastfeeding will support placental separation and control bleeding due to the release of oxytocin resulting in uterine contraction

Question 5

What are 5 factors that may interfere with physiological processes of the third stage of labour?

Answer 5

• Previous postpartum haemorrhage
• Anaemia
• Clotting disorders
• Dehydration during labour
• Long 1st or 2nd stage of labour

Question 6

What is active management?

Answer 6

• Intramuscular uterine tonic: syntocinon or syntometrine
• Given at the birth of the anterior shoulder or immediately after birth of the baby, some midwives delay this until after OCC (optimal cord clamping)
• The transfer of blood to baby is unaffected by uterotonics, so don’t be hesitant is uterotonics advised
• Observe for signs of separation: lengthening of cord, uterine cramps, PV bleed
• Controlled cord tractions
• Reduces blood loss by 66% but unclear whether reduces risk of primary haemorrhage

Question 7

What is a retained placenta?

Answer 7

After vaginal delivery if the placenta does not spontaneously deliver within a designated amount of time, usually between 18-60mins or if a patient experiences significant haemorrhage prior to delivery of the placenta they will be diagnosed with retained placenta

Question 8

What risk factors are related to poor uterine contraction?

Answer 8

• High parity
• Prolonged use of oxytocin

Question 9

What risk factors are related to abnormal placentation?

Answer 9

• History of uterine surgery
• IVF conception
• Preterm delivery
• Congenital uterine anomaly
• Prior history of retained placenta

Question 10

What should you examine about the placenta?

Answer 10

• Shape
• Size
• Texture
• Cord – its vessels, length, insertion, abnormalities
• Membranes – the chorion & the amnion
• Completion

Question 11

What carries oxygenated blood from the the placenta to the neonate?

Answer 11

The umbilical vein

Question 12

What carries deoxygenated blood from the neonate to the placenta?

Answer 12

The 2 umbilical arteries