Placenta Praevia Flashcards
What is placenta praevia?
When the placenta is attached to the lower uterine segment, lower than the presenting part of the fetus
What is the main complication of placenta praevia?
Antepartum haemorrhage
What is antepartum haemorrhage?
Vaginal bleeding from week 24 of gestation until delivery
What are the four classifications of placenta praevia?
Minor Praevia
Marginal Praevia
Partial Praevia
Complete Praevia
What is minor praevia (grade one)?
A placenta in the lower uterus that doesn’t reach the internal cervical os
What is marginal praevia (grade two)?
A placenta which reaches, however doesn’t cover, the internal cervical os
What is partial praevia (grade three)?
A placenta which partially covers the internal cervical os – specifically covering before dilation however not when dilated
What is complete praevia (grade four)?
A placenta which completely covers the internal cervical os
What is the difference between low-lying placenta and placenta praevia?
Low-lying placenta is the term used when the placenta is within 20mm of the internal cervical os
Placenta praevia is the term used when the placenta is over the internal cervical os
What are the five risk factors of placenta praevia?
Previous C-Section
Maternal Age > 40
Multiple Pregnancy
Multiparity
Previous Placenta Praevia
What is the most common risk factor of placenta praevia?
Previous C-Section
What are the two clinical features associated with placenta praevia?
Painless Vaginal Bleeding
Shock
What is the cause of bleeding in placenta praevia?
This bleeding is due to separation of the placenta, as the lower uterine segment forms and the cervix effaces
Which blood vessels rupture in placenta praevia?
Venous sinuses in the lower segment
What are the two features of shock?
Tachycardia
Hypotension
What are the two investigations used to diagnose placenta praevia?
Abdominal Ultrasound Scan
Transvaginal Ultrasound Scan
When are abdominal ultrasound scans used to diagnsoe placenta praevia?
They detect placenta praevia at the routine 20 weeks scan
What is the gold standard investigation is used to diagnose placenta praevia?
Transvaginal US scan
What are the three features of placenta praevia on US scan?
Reduced Distance Between Placenta & Internal Cervical Os
Abnormal Fetal Lie & Presentation
Normal Fetal Heartbeat
Do we conduct vaginal examination for placenta praevia diagnosis? Why?
No
There is an increased risk of severe haemorrhage
How do we manage a low-lying placenta which presents on the 20 week abdominal ultrasound scan?
We conduct a transvaginal ultrasound scan at 32 weeks
In cases where the placenta praevia is still present at 32 weeks, we rescan every 2 weeks following this
Once 36 weeks gestation, a final ultrasound scan is used to determine the method of delivery
What delivery method is recommended in grade one placenta praevia patients?
Vaginal Delivery
What delivery method is recommended in grade three and four placenta praevia patients? When should this be conducted?
Elective C-sections
37 - 38 weeks gestation
How do we manage placenta praevia, with active bleeding?
Admit
ABC Approach
In which two cirucmstances is emergency c-section recommended to manage placenta praevia patients, with active bleeding?
Unstable > ABC Approach
Labour
When do we prescribe anti-d to placenta praevia patients?
Within 72 hours of bleeding - if the woman is rhesus D negative
What are the four complications of placenta praevia?
Antepartum Haemorrhage
Postpartum Haemorrhage
Preterm Labour
Stillbirth
