Placental diseases

Question 1

What is antepartum haemorrhage (APH)?

Answer 1

Bleeding from the genital tract after 24 weeks before onset of labour

Question 2

Causes of APH?

Answer 2

Common:

1. Undetermined origin
2. Placental abruption
3. Placenta praevia

Rare:

1. Incidental genital tract pathology
2. Uterine rupture
3. Vasa praevia

Question 3

What is placenta praevia?

Answer 3

Occurs when the placenta is implanted in the lower segment of the uterus

Question 4

What is marginal placenta praevia?

Answer 4

The placenta is in the lower segment of the uterus, but not covering the os

Question 5

What is major placenta praevia?

Answer 5

The placenta is completely or partially covering the os

Question 6

What makes placenta praevia more common?

Answer 6

1. Twins
2. High parity
3. Older age
4. Scarred uterus (e.g. previous c-section)

Question 7

How severe are haemorrhages due to placenta praevia and why?

Answer 7

Can be severe and may continue during and after delivery as the lower segment is less able to contract and constrict the maternal blood supply

Question 8

What can happen if the placenta implants in a previous c-section scar?

Answer 8

It may be so deep as to prevent placental separation (placenta accreta) or even penetrate through the uterine wall into surrounding such as the bladder (placenta percreta)

Question 9

Hx of placenta praevia?

Answer 9

1. Intermittent painless bleeds, which increase in frequency and intensity over several weeks
2. Bleeding may be severe

Question 10

Examination of placenta praevia?

Answer 10

1. Breech presentation and transverse lie are common

2. Foetal head not engaged and high

Question 11

Why should vaginal exam never be performed on a bleeding pregnant woman until placenta praevia is excluded?

Answer 11

As it can cause massive bleeding

Question 12

How is a diagnosis of placenta praevia made?

Answer 12

USS

Question 13

Presentations of placenta praevia?

Answer 13

1. Incidental finding on USS
2. Vaginal bleeding
3. Abnormal lie, breech presentation

Question 14

What is done to assess maternal and foetal wellbeing in placenta praevia?

Answer 14

1. Cardiotocography (CTG)
2. FBC
3. Clotting studies
4. Cross match

Question 15

What is the mode of delivery in placenta praevia?

Answer 15

Elective c-section

Question 16

Hx that should be taken in an APH?

Answer 16

1. Gestational age
2. Amount of bleeding (but don’t forget about concealed abruption)
3. Associated or initiating factors (coitus/trauma)
4. Abdominal pain
5. Foetal movements
6. Date of last smear
7. Previous episodes of PV bleeding in this pregnancy
8. Leakage of fluid PV
9. Previous uterine surgery (including c-section)
10. Smoking and illegal drug use (especially cocaine)
11. Blood group and rhesus status (anti-D needed)
12. Previous obstetric Hx (placental abruption, intrauterine growth restriction, placenta praevia)
13. Position of placenta, if known from previous scan

Question 17

When is retained placenta suspected?

Answer 17

If placenta is not delivered within 30 mins of the baby in an actively managed 3rd stage and 1h in a physiological 3rd stage

Question 18

Mx of retained placenta?

Answer 18

IV access, FBC and cross-match
Give oxytocin
If oxytocin not effective in 30mins, transfer to theatre for regional block and manual removal of placenta
Intraoperative prophylactic Abx should be given

Question 19

What is placenta accreta?

Answer 19

Placental villi are attached to the myometrium

Question 20

What is placenta increta?

Answer 20

Villi invaded into >50% of the myometrium

Question 21

What is placenta percreta?

Answer 21

Villi pass through the whole myometrium up to the serosa, potentially involving other viscera (bladder or bowel)

Question 22

RFx for placenta accreta?

Answer 22

1. Uterine surgery such as CS or myomectomy

2. Repeated surgical termination of pregnancy