Placenta Accreta Flashcards
Definition
When the placenta implants deeper, through and past the endometrium, making it difficult to separate the placenta after delivery of the baby.
Why is it referred to as placenta accreta spectrum
As there is a spectrum of severity in how deep and broad the abnormal implantation extends
Anatomy of uterus
There are three layers of the uterine wall
- Endometrium = inner layer, contains connective tissue (stroma), epithelial cells and blood vessels
- Myometrium, the middle layer that contains smooth muscle
- Perimetrium, the outer layer, which is a serous membrane similar to the peritoneum (also known as serosa)
Superficial placenta accreta
Where the placenta implants in the surface of the myometrium, but not beyond
Placenta increta
Where the placenta attaches deeply into the myometrium
Placenta percreta
Where the placenta invades past the myometrium and perimetrium, potentially reaching other organs such as the bladder
Risk factors
- 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
Clinical features
ASx
- Can present with bleeding (anterpartum haemorrhage) in third trimester
Diagnosis
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
Management
Additional management at birth to prevent risk of bleeding:
- Complex uterine surgery
- Blood transfusions
- Intensive care for mothers
- Neonatal intensive care
Birth plan
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.
Expectant management
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.