Third Stage of Labour

Question 1

Define the third stage of labour

Answer 1

From the expulsion of the fetus to the expulsion of the placenta and membranes, and the control of bleeding and examination of the perineum

Question 2

Describe the process of placental separation

Answer 2

Placenta squeezed → blood in intervillous spaces forced back into veins of decidua → congested decidual veins burst → blood seeps out → separates placenta from decidual lining → uterus contracts and reduces surface area → placenta sheers/falls away at lining of decidua balasis → falls into uterine cavity and peels membranes away

Question 3

What is the Schulzte method of separation?

Answer 3

Separation begins centrally, a retroplacental clot forms behind. Separation aided by increased weight, more complete and less blood loss.

Question 4

Describe the Matthew Duncan method of separation?

Answer 4

Detaches from lateral edge, associated with ragged, incomplete expulsion, higher blood loss.

Question 5

What are the signs of placental separation?

Answer 5

Trickle of blood per vagina as the placenta separates, lengthening of the cord, may be a sensation of wanting to push, uterus becomes hard and mobile

Question 6

How is bleeding controlled?

Answer 6

Reduction in blood supply - contractions of the uterine myometrium compress blood vessels supplying the placental site (living ligatures)

A cut vessel immediately constricts
Opposing endothelial surfaces become sticky and adhere
Pressure from uterine surfaces
Platelet plug forms

Question 7

Describe blood clotting in the third stage

Answer 7

Major changes occur in the coagulation and fibrinolytic systems during pregnancy and labour
Marked increase in clotting factors
Increase in fibrinogen
Reduced clotting time
Fibrin mesh rapidly covers placental site

Question 8

Effects of enhanced clotting

Answer 8

Thromboembolism

Increased concentration of clotting factors postpartum

LSCS, risk of immobility, dehydration, infection exacerbated

Mobilisation and thrombophrophylaxis

Question 9

Physiological management of the third stage

Answer 9

No administration of uterotonic drug

Cord not clamped until pulsating has ceased

Placenta delivered by gravity or maternal effort

Question 10

Active management of the third stage

Answer 10

Use of oxytonic drug

NICE recommend oxytocin 10iu but some trusts use Syntometrine

Controlled cord traction after signs of separation

Placenta delivered without the aid of gravity