Placenta praevia Flashcards
Definition
Where the placenta is attached to the lower portion of the uterus, lower than the presenting part of the foetus.
Low lying placenta definition
Where the placenta is withitn 20mm of internal cervical os.
Placenta praevia definition
Only when the placenta is over the internal cervical os.
Risk factors
- Previous caesarean sections
- Previous placenta praevia
- Older maternal age
- Maternal smoking
- Structural uterine abnormalities (e.g. fibroids)
- Assisted reproduction (e.g. IVF)
Aetiology of spotting or minor bleeding in pregnancy
- Cervical ectropion
- Infection and vaginal abrasions from intercourse or procedures
Aetiology of anternatal haemorrhage
- Placenta praevia
- Placental abruption
- Vasa praevia
Grades
- 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
Clinical features
Many ASx
- May present with painless vaginal bleeding in pregnancy (antepartum haemorrhage).
- Bleeding usually occurs later in pregnancy (around or after 36 weeks).
Diagnosis
20-week anomaly scan used to assess the position of the placenta and diagnose placenta praevia.
Treatment
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 (<20mm from the internal os)
USS around time of procedure to locate the placenta
Emergancy c-section = premature labour or antenatal bleeding
Complications
- Antepartum haemorrhage
- Emergency caesarean section
- Emergency hysterectomy
- Maternal anaemia and transfusions
- Preterm birth and low birth weight
- Stillbirth
Treatment of haemorrhage
- Emergency caesarean section
- Blood transfusions
- Intrauterine balloon tamponade
- Uterine artery occlusion
- Emergency hysterectomy