Placenta praevia

Question 1

Defintion

Answer 1

Where the placenta is attached to the lower portion of the uterus, lower than the presenting part of the foetus.

Question 2

Low lying placenta definition

Answer 2

Where the placenta is withitn 20mm of internal cervical os.

Question 3

Placenta praevia definition

Answer 3

Only when the placenta is over the internal cervical os.

Question 4

Aetiology of anternatal haemorrhage

Answer 4

• Placenta praevia
• Placental abruption
• Vasa praevia

Question 5

Aetiology of spotting or minor bleeding in pregnancy

Answer 5

• Cervical ectropion
• Infection and vaginal abrasions from intercourse or procedures

Question 6

Complications

Answer 6

• Antepartum haemorrhage
• Emergency caesarean section
• Emergency hysterectomy
• Maternal anaemia and transfusions
• Preterm birth and low birth weight
• Stillbirth

Question 7

Grades

Answer 7

• Minor praevia, (grade I) = placenta is in lower uterus but not reaching the internal cervical os
• Marginal praevia, (grade II) – placenta is reaching, but not covering, the internal cervical os
• Partial praevia, (grade III) = placenta is partially covering the internal cervical os
• Complete praevia (grade IV) = placenta is completely covering the internal cervical os

Question 8

Risk factors

Answer 8

• Previous caesarean sections
• Previous placenta praevia
• Older maternal age
• Maternal smoking
• Structural uterine abnormalities (e.g. fibroids)
• Assisted reproduction (e.g. IVF)

Question 9

Clinical features

Answer 9

Many ASx
- May present with painless vaginal bleeding in pregnancy (antepartum haemorrhage).
- Bleeding usually occurs later in pregnancy (around or after 36 weeks).

Question 10

Diagnosis

Answer 10

20-week anomaly scan used to assess the position of the placenta and diagnose placenta praevia.

Question 11

Treatment

Answer 11

For women with low-lying placenta or PP diagnosed in early pregnancy: RCOG recommend TVUS
- 32 weeks gestation
- 36 weeks gestation
Corticosteroids = help mature lungs
Planned delivery between 36-37 weeks to reduce risk of spontaneous labour and bleeding.
Planned c-section = when PP + low lying placenta (<29mm from the internal os)
USS around time of procedure to locate the placenta
Emergancy c-section = premature labour or antenatal bleeding

Question 12

Complications

Answer 12

Haemorrhage before or after delivery

Question 13

Treatment of haemorrhage

Answer 13

• Emergency caesarean section
• Blood transfusions
• Intrauterine balloon tamponade
• Uterine artery occlusion
• Emergency hysterectomy