Placenta Accreta

Question 1

Definition

Answer 1

When the placenta implants deeper, through and past the endometrium, making it difficult to separate the placenta after delivery of the baby.

Question 2

Why is it referred to as placenta accreta spectrum

Answer 2

As there is a spectrum of severity in how deep and broad the abnormal implantation extends

Question 3

Pathophysiology

Answer 3

There are three layers of the uterine wall
- Endometrium = inner layer, contains connective tissue (stroma), epithelial cells and blood vessels
- Myometrium, the

Question 4

Physiology

Answer 4

Usually the placenta attaches to the endometrium. This allows the placenta to separate cleanly during the third stage of labour, after delivery of the baby.

Question 5

Superficial placenta accreta

Answer 5

Where the placenta implants in the surface of the myometrium, but not beyond

Question 6

Placenta increta

Answer 6

Where the placenta attaches deeply into the myometrium

Question 7

Placenta percreta

Answer 7

Where the placenta invades past the myometrium and perimetrium, potentially reaching other organs such as the bladder

Question 8

Risk factors

Answer 8

• Previous placenta accreta
• Previous endometrial curettage procedures (e.g. for miscarriage or abortion)
• Previous caesarean section
• Multigravida
• Increased maternal age
• Low-lying placenta or placenta praevia

Question 9

Clinical features

Answer 9

ASx
- Can present with bleeding (anterpartum haemorrhage) in third trimester

Question 10

Diagnosis

Answer 10

Antenatal USS scan
- Attention given to women with a previous P.A or C-section during scanning
Can be diagnosed at birth, when it becomes difficult to deliver the placenta = cause significant postpartum haemorrhage.
MRI = can be used to assess depth and width of the invasion

Question 11

Management

Answer 11

Additional management at birth to prevent risk of bleeding:
- Complex uterine surgery
- Blood transfusions
- Intensive care for mothers
- Neonatal intensive care

Question 12

Birth plan

Answer 12

Delivery planned between 35-36 + 6 weeks to reduce risk of spontaneous labour and delivery.
Antenatal steroids = mature lungs
The options during caesarean are:
- Hysterectomy with placenta remaining in the uterus (recommended)
- Uterus preserving surgery, with resection of part of the myometrium along with the placenta
- Expectant management, leaving the placenta in place to be reabsorbed over time.

Question 13

Expectant management

Answer 13

RCOG guideline (2018) = when opening the abdomen in elective c-section, if P.A seen = the abdomen can be closed and delivery delayed whilst specialist services put in place.
- If placenta accreta is discovered after delivery of the baby, a hysterectomy is recommended.