Placenta Praevia

Question 1

Placenta previa is when the placenta is wholly or partially attached to the lower uterine segment. How many classes of placenta previa are there?

1 - 6
2 - 4
3 - 2
4 - 1

Answer 1

3 - 2

• partial = part of placenta covers internal os
• complete = whole placenta covers internal os

Question 2

What is the incidence of placenta previa?

1 - 40-50%
2 - 25-30%
3 - 5-10%
4 - 0.4-0.8%

Answer 2

4 - 0.4-0.8%
- peak incidence is in 30-40 y/o

Question 3

The incidence of placenta previa is 0.4-0.8%, but which of the following is NOT a risk factor that increases the risk of placenta previa?

1 - previous c-section
2 - nulliparity
3 - previous placenta previa
4 - advanced age
5 - multiple pregnancy
6 - smoking
7 - succenturiate placenta lobe

Answer 3

2 - nulliparity
- multiparty is a risk factor

Question 4

What is the reoccurrence rate of placenta previa in future pregnancies?

1 - 0.4-0.8%
2 - 4-8%
3 - 15-20%
4 - 30-40%

Answer 4

2 - 4-8%

Question 5

In addition to the placenta previa, patients who have had multiple C-sections may also experience placenta accreta. What is this?

1 - placenta develops on fundus but blocks fallopian tubes
2 - placenta detaches from uterine wall
3 - placenta grows too deeply into the uterine wall
4 - can be all of the above

Answer 5

3 - placenta grows too deeply into the uterine wall

Question 6

In patients with placenta previa, they may be completely asymptomatic and it may only be detected during routine imaging. However, what is the most common presentation?

1 - abdominal mass
2 - pelvic pain, vaginal bleeding and UTI
3 - UTI and pelvic pain
4 - painless vaginal bleeding

Answer 6

4 - painless vaginal bleeding
- ranges from spotting to life threatening haemorrhage
- uterus is typically non-tender and soft

Question 7

If symptoms of placenta previa do present with painless vaginal bleeding, which trimester do they typically occur in?

1 - 3rd
2 - 2nd
3 - 1st

Answer 7

1 - 3rd
- mean is 30 weeks gestation

Question 8

How is placenta previa diagnosed?

1 - bimanual examination
2 - abdominal ultrasound
3 - pregnant abdominal examination
4 - blood test

Answer 8

2 - abdominal ultrasound

Question 9

Abdominal ultrasound typically diagnoses placenta previa. When is it typically picked up?

1 - week 12
2 - week 20
3 - week 28
4 - week 32

Answer 9

2 - week 20
- anomaly scan
- if identified, then scanned again at week 32 weeks to make diagnosis

Question 10

If a women is pregnant and presents with vaginal bleeding, which of the following is an unlikely differential diagnosis?

1 - miscarriage
2 - placenta abruption
3 - adenomyosis
4 - cervical ectropian

Answer 10

3 - adenomyosis
- does not typically cause vaginal bleeding in pregnancy

Question 11

Do all placenta previa remain throughout pregnancy?

Answer 11

• no
• 90% of cases resolve spontaneously

Question 12

If bleeding is heavy and placenta previa is suspected, what examination must NOT be performed?

1 - digital examination
2 - ultrasound
3 - group and save and crossmatch
4 - rectal examination

Answer 12

1 - digital examination
- may cause major haemorrhage

• if only minor bleeding, a speculum may be used to examine the patient

Question 13

Which tests must be performed in a patient with placenta previa and risk of bleeding?

1 - FBC
2 - coagulation profile
3 - group and save and crossmatch
4 - rhesus status
5 - all of the above

Answer 13

5 - all of the above

Question 14

What tells the doctor that the baby is ok?

1 - ultrasound
2 - maternal feeling of movement
3 - CTG
4 - all of the above

Answer 14

4 - all of the above

Question 15

What test can be used to assess for the presence of foetal blood in maternal circulation, which can occur during haemorrhage and affects Rhesus status?

1 - FBC
2 - Kleihauer test
3 - blood smears
4 - blood cross matching

Answer 15

2 - Kleihauer test

Question 16

Why should renal function be assessed in individuals with placenta previa?

1 - risk of hypovolaemia
2 - risk of polyhidrosis
3 - risk of pyelonephritis
4 - all of the above

Answer 16

1 - risk of hypovolaemia
- will see low urine output and drop in BP due to excessive blood loss, cause kidney injury

Question 17

All patients who are diagnosed with placenta previa should be advised to avoid which of the following?

1 - penetrative intercourse
2 - vaginal douching
3 - vaginal examination unless necessary
4 - all of the above

Answer 17

4 - all of the above

Question 18

If there is maternal or foetal compromise when the mother begins to bleed, what should occur asap?

1 - vaginal birth
2 - abortion to save the mother
3 - c-section
4 - any of the above

Answer 18

3 - c-section

Question 19

A c-section may be needed if a patient has placenta previa. What distance from the internal os is generally an indication that a c-section should be performed?

1 - <0.5mm
2 - <2cm
3 - <4cm
4 -<6cm

Answer 19

2 - <2cm
- if 2cm or closer to internal os, c-section is advised

• Prophylactic and intra-operative antibiotics are recommended.

Question 20

Is a c-section required in all patients with placenta previa?

Answer 20

• no
• if baby becomes engaged and head passed edge of placenta, vaginal birth may be necessary

Question 21

In a patient with placenta previa, they may need to deliver earlier than planned if they experience vaginal bleeding. The mother may be given corticosteroids to help develop the foetus lungs. Below what week of gestation should corticosteroids be given if the baby needs to be delievred?

1 - <38 weeks
2 - <37 weeks
3 - <35 weeks
4 - <34 weeks

Answer 21

4 - <34 weeks

Question 22

In a patient with placenta previa, what medication may be given in an attempt to delay labour to provide maximum benefit from corticosteroids therapy for the foetus?

1 - Oxytocins
2 - Prostaglandins
3 - Hormone inhibitors
4 - Tocolytics

Answer 22

4 - Tocolytics
- induce smooth muscle relaxation, so stop contractions

Question 23

Pregnant women who has develop vaginal bleeding with placenta previa and who are rhesus negative should be given anti-D within what time frame from the onset of bleeding?

1 - <12 hours
2 - <48 hours
3 - <72 hours
4 - <120 hours

Answer 23

3 - <72 hours

Question 24

What is the major maternal risk factor in a patient with placenta previa?

1 - sepsis
2 - post-partum haemorrhage
3 - uterine rupture
4 - UTI

Answer 24

2 - post-partum haemorrhage
- lower uterus does not contract as well, therefore venous sinuses are not as efficiently occluded