PLACENTA PRAEVIA

Question 1

What is placenta praevia?

Answer 1

Placenta praevia describes a placenta lying wholly or partly in the lower uterine segment.

Question 2

What percentage of pregnancies have a low-lying placenta at 16-20 weeks gestation?

Answer 2

5% of pregnancies have a low-lying placenta at 16-20 weeks gestation.

Question 3

What is the incidence of placenta praevia at delivery?

Answer 3

The incidence of placenta praevia at delivery is only 0.5%.

Question 4

What factors are associated with an increased risk of placenta praevia?

Answer 4

Factors associated with an increased risk of placenta praevia include multiparity, multiple pregnancy, and embryos more likely to implant on a lower segment scar from a previous caesarean section.

Question 5

What are the clinical features of placenta praevia?

Answer 5

Clinical features of placenta praevia include shock in proportion to visible loss, no pain, non-tender uterus, abnormal lie and presentation, usually normal fetal heart, rare coagulation problems, and small bleeds before large.

Question 6

Why should digital vaginal examination not be performed before an ultrasound in suspected placenta praevia?

Answer 6

Digital vaginal examination should not be performed before an ultrasound in suspected placenta praevia as it may provoke a severe haemorrhage.

Question 7

When is placenta praevia often picked up?

Answer 7

Placenta praevia is often picked up on the routine 20-week abdominal ultrasound.

Question 8

What does the RCOG recommend for improving the accuracy of placental localisation?

Answer 8

The RCOG recommends the use of transvaginal ultrasound as it improves the accuracy of placental localisation and is considered safe.

Question 9

What is the classical grading of placenta praevia?

Answer 9

The classical grading of placenta praevia includes Grades I to IV.

Question 10

Describe Grade I placenta praevia.

Answer 10

Grade I placenta praevia is when the placenta reaches the lower segment but not the internal os.

Question 11

Describe Grade II placenta praevia.

Answer 11

Grade II placenta praevia is when the placenta reaches the internal os but doesn’t cover it.

Question 12

Describe Grade III placenta praevia.

Answer 12

Grade III placenta praevia is when the placenta covers the internal os before dilation but not when dilated.

Question 13

Describe Grade IV placenta praevia.

Answer 13

Grade IV (‘major’) placenta praevia is when the placenta completely covers the internal os.