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Flashcards in Placenta Praevia Deck (71)
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1
Q

What is placenta praevia?

A

Where the placenta is fully or partially attached to the lower uterine segment

2
Q

Why is placenta praevia clinically important?

A

Because it is an important cause of antepartum haemorrhage

3
Q

What are the main types of placenta praevia?

A
  • Minor

- Major

4
Q

What is minor placenta praevia?

A

Placenta is low, but does not cover the internal cervical os

5
Q

What is major placenta praevia?

A

Placenta lies over the internal cervical os

6
Q

What is the problem with placenta praevia?

A

A low lying placenta is more susceptible to haemorrhage

7
Q

Why is a low lying placenta more susceptible to haemorrhage?

A

Possibly due to defective attachment to the uterine wall

8
Q

What can cause the bleeding in placenta praevia?

A
  • Spontaneous
  • Provoked by mild trauma, e.g. vaginal examination
  • Damage as presenting part of the fetus moves into the lower uterine segment in preparation for labour
9
Q

What is the main risk factor for placenta praevia?

A

Previous C-section

10
Q

What is the incidence of placenta praevia with 1 previous C-section?

A

1 in 160

11
Q

What is the incidence if placenta praevia with 2 previous C-sections?

A

1 in 60

12
Q

What is the incidence of placenta praevia with 4 previous C-sections?

A

1 in 10

13
Q

What are the other risk factors for placenta praevia?

A
  • High parity
  • Maternal age >40 years
  • Multiple pregnancy
  • Previous placenta praevia
  • History of uterine infection (endometritis)
  • Curettage of endometrium after miscarriage or termination
14
Q

How might placenta praevia be detected if asymptomatic?

A

May be incidental finding on routine anomaly ultrasound

15
Q

How does placenta praevia classically present?

A

Painless vaginal bleeding

16
Q

How severe is the vaginal bleeding in placenta praevia?

A

Varies from spotting to massive haemorrhage

17
Q

When might there be pain in placenta praevia?

A

If the woman is in labour

18
Q

What might examination reveal in placenta praevia?

A

Risk factors pertinent to placenta praevia, e.g. c-section scar or multiple pregnancy

19
Q

Is the uterus tender on palpation in placenta praevia?

A

Not usually

20
Q

What are the differentials for placenta praevia?

A
  • Placental abruption
  • Vasa praevia
  • Uterine rupture
  • Local genital causes
21
Q

What is vasa praevia?

A

Where fetal blood vessels run near the internal cervical os

22
Q

What is vasa praevia characterised by?

A

Triad of;

  • Vaginal bleeding
  • Rupture of membranes
  • Fetal compromise
23
Q

When does the bleeding occur in vasa praevia?

A

Following the rupture of membranes

24
Q

Why does the bleeding occur following the rupture of membranes in vasa praevia?

A

Because there is rupture of umbilical cord vessels

25
Q

What does the rupture of umbilical cord vessels in vasa praevia lead to?

A

A loss of fetal blood and rapid deterioration in fetal condition

26
Q

What local genital causes are differentials for placenta praevia?

A
  • Benign or malignant lesions

- Infections

27
Q

What benign or malignant lesions can be differentials for placenta praevia?

A
  • Polyps
  • Carcinoma
  • Cervical ectropion
28
Q

What infections can be differentials for placenta praevia?

A
  • Candida
  • BV
  • Chlamydia
29
Q

What should be done regarding investigations if major bleeding is suspected?

A

Perform investigations and resuscitate simultaneously

30
Q

What investigations should be done in placenta praevia?

A
  • Bloods
  • Assess fetal wellbeing
  • Imaging
31
Q

What bloods should be done in placenta praevia?

A
  • FBC
  • Clotting profile
  • Kleihauer test
  • G&S
  • Crossmatch
  • U&Es and LFTs
32
Q

Why should FBC be done in placenta praevia?

A

To asses for any maternal anaemia

33
Q

When should Kleihauer test be done in placenta praevia?

A

If the woman is rhesus negative

34
Q

What does the Kleihauer test determine?

A

The amount of feto-maternal haemorrhage

35
Q

Why is it important to determine the amount of feto-maternal haemorrhage in rhesus negative women?

A

To determine the dose of anti-D required

36
Q

When is crossmatch required in placenta praevia?

A

If clinical presentation is likely to warrant transfusion

37
Q

Why are U7Es and LFTs done in suspected placenta praevia?

A

To exclude pre-eclampsia and HELLP syndrome, and any other organ dysfunction

38
Q

How should an assessment of fetal wellbeing be made in women above 26 weeks?

A

CTG

39
Q

How is the definitive diagnosis of placenta praevia made?

A

Ultrasound

40
Q

What will be shown on ultrasound in placenta praevia?

A

Short distance between lower edge of placenta and internal os

41
Q

How is minor placenta praevia managed?

A

Repeat scan at 36 weeks is recommended

42
Q

Why is a repeat scan at 36 weeks recommended in minor placenta praevia?

A

As the placenta is likely to have moved

43
Q

What repeat scanning is recommended in major placenta praevia?

A

Repeat at 32 weeks

44
Q

Why is the scan repeated at 32 weeks in major placenta praevia?

A

As a plan for delivery is made at this time

45
Q

What is required for delivery in placenta praevia?

A

C-section

46
Q

What should women with major placenta praevia be advised not to do?

A

Have penetrative sexual intercourse

47
Q

What decision has to made in women with major placenta praevia?

A

About location of care after 34 weeks gestation

48
Q

Who can potentially receive outpatient care with major placenta praevia?

A

Women who remain asymptomatic, i.e. no bleeding

49
Q

What do women with major placenta praevia who are considering outpatient care require to make their decision?

A

Careful counselling

50
Q

What are the requirements for outpatient care for major placenta praevia after 36 weeks?

A
  • Close proximity to the hospital
  • Constant companion
  • Fully informed consent of the woman
51
Q

When should a woman receiving home-based care for major placenta praevia be advised to visit the hospital immediately?

A

If she experiences any bleeding, contractions, or pain

52
Q

Which patients with major placenta praevia should be encouraged to stay in hospital from 34 weeks gestation?

A

Women who have experienced a bleed

53
Q

When should C-section be performed for placenta praevia?

A

Where possible, should be deferred to 38 weeks

54
Q

Why should the C-section be deferred to 38 weeks in placenta praevia?

A

To minimise neonatal morbidity

55
Q

What should be considered when planning the timing of elective C-section in placenta praevia?

A

The benefits of additional maturity should be weighed against the risk of major haemorrhage and the possibility that repeated small haemorrhage can cause IUGR

56
Q

What is placenta accreta?

A

Morbidly adherent placenta

57
Q

Who has a high risk of placenta accreta?

A

Women with placenta praevia who have previously had a C-section

58
Q

When should placenta accreta be considered as a possible diagnosis?

A

In any situation where any part of the placenta lies under the previous C-section scar, even if not praevia

59
Q

How can a definitive diagnosis of placenta accreta be made?

A

Only at surgery

60
Q

How should a C-section be performed if there is suspicion of placenta accreta?

A

The uterus should be opened at a site distant to the placenta, and the baby should be born without disturbing the placenta

61
Q

Why should a C-section be performed without disturbing the placenta in placenta accreta

A

Because it allows either conservative management of the placenta, or hysterectomy if accreta is confirmed

62
Q

What should you not do when there is acute bleeding associated with placenta praevia?

A

Perform a vaginal examination

63
Q

Why should you not perform a vaginal examination when there is acute bleeding associated with placenta praevia?

A

As this may start torrential bleeding

64
Q

What needs to be considered regarding blood loss in acute bleeding caused by placenta praevia?

A

Should assess blood loss and cross-match for possible transfusion

65
Q

What is indicated in acute bleeding caused by placenta praevia?

A

Resuscitation

66
Q

Who is the priority when resuscitating because of acute blood loss caused by placenta praevia?

A

The mother

67
Q

What should be done as a result of the mother being the priority in resuscitation for acute blood loss caused by placenta praevia?

A

The mother should be stabilised before any assessment of the fetus

68
Q

What surgical intervention may be required in acute bleeding caused by placenta praevia?

A

In severe bleeding, the baby is delivered urgently, whatever its gestational age
Hysterectomy may be required in severe cases

69
Q

What should be done if the patient is bleeding due to placenta praevia, but immediate delivery is not likely?

A

Maternal steroids may be indicated

70
Q

Why might maternal steroids be indicated when bleeding due to placenta praevia but immediate delivery not likely?

A

To promote fetal lung development and reduce the risk of respiratory distress syndrome and IV haemorrhage

71
Q

What are the potential complications of placenta praevia?

A
  • Potentially fatal hypovolaemic shock

- Fetal haemorrhage, prematurity, intrauterine asphyxia, or birth injury

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