Third Stage Of Labour

Question 1

Define the third stage

Answer 1

Period from the birth of the baby through to the delivery of the placenta and membranes and ending with the control of bleeding.

Question 2

Outline the process of the third stage

Answer 2

Fetus is delivered
Placental site reduces by half its former size
Reduction in support base leads to compression and shearing of the placenta from the uterine wall
Placenta is compressed so blood in the intravillois spaces is forced back into the decidua
Retraction of oblique and circular uterine muscle fibres
Uterus reduces in bulk size
Materno-placental blood vessels tear
Placenta becomes wrinkled and peels away from uterine wall
Placenta separates but held in suspension by membranes

Question 3

Outline the separation process

Answer 3

Placenta held in suspension by membranes
Gravity and maternal effort means the placenta descends into the lower undermine segment
Membranes peel from uterine wall as they follow the placenta
Small bleed results
Placenta followed by membranes pass through the cervix to vagina
Placenta and membranes expelled to exterior by gravity, maternal effort and cord traction

Question 4

Describe the Schultz method

Answer 4

Fundal placenta
Origin of cord appears at vulva
Followed by fetal surface
(Shiny Schultz)

Question 5

Outline the Matthews-Duncan method

Answer 5

Lateral placenta
Edge of placenta slides out
Followed by rest of maternal side, cord and membranes
Origin of cord not seen until expulsion
(Dirty Duncan)

Question 6

List the signs of placental separation

Answer 6

Gush of blood
Lengthening of cord
Fundus rises and becomes spherical

Question 7

How is haemostasis obtained?

Answer 7

Living ligatures - reduce blood flow to the placental site by the tourniquet action of the myometrial muscle fibres on maternal vessels
Pressure - once placenta has left the upper segment, sting uterine contraction brings walls of uterus in opposition and compresses the placental site
Partial recoil of spiral uterine arteries reduces blood flow to the uterus and placental site
Blood clotting - during birth process and immediately after there is an increase in coagulation system
fibrin plugs form in the ends of severed vessels
Fibrin mesh rapidly covers placental site

Question 8

What is the average blood loss?

Answer 8

300ml

Question 9

What can assist placental separation?

Answer 9

Breastfeeding

Question 10

What classes as a haemorrhage?

Answer 10

500ml +