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Introduction

Placental abruption is a cause of antepartum haemorrhage (defined as bleeding > 24 weeks gestation) and defined as premature separation of a normally sited placenta from the uterine wall, resulting in maternal haemorrhage into the intervening space.

Placental abruption occurs in 0.3% to 1% of births.

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Aetiology

The cause of placental abruption is not known. Abruption is more likely to occur in the last trimester, particularly during the last few weeks prior to birth.

Placental abruption can be either concealed (bleeding remains within the uterus and is not visible) or revealed (visible vaginal bleeding).

Placental abruption
Figure 1. Revealed (with external bleeding) and concealed (with internal bleeding) placental abruption.3

Risk factors

Risk factors for placental abruption include:4

  • Previous history of placenta abruption
  • Pre-eclampsia
  • Fetal complications: fetal growth restriction, non-vertex presentations, polyhydramnios
  • Advanced maternal age
  • Multiparity
  • Low maternal body mass index (BMI)
  • Pregnancy following assisted reproductive techniques
  • Intrauterine infection
  • Premature rupture of membranes
  • Abdominal trauma (both accidental and resulting from domestic violence)
  • Smoking and drug misuse (cocaine and amphetamines) during pregnancy

Clinical features

History

The typical presentation of placental abruption is sudden constant pain with or without dark red vaginal bleeding (>24 weeks gestation).

Other important areas to cover in the history include:

  • Rupture of membranes: if has occurred, consider vasa praevia
  • Provoking factors (e.g. post-coital)
  • Fetal movements
  • Risk factors (e.g. smoking/drug use)
  • Obstetric history: previous pregnancies, delivery mode, gestation and complications
  • Past medical history
  • Conception history: IVF

Clinical examination

A digital vaginal examinationย should not be performed, as this may trigger heavy bleeding in unconfirmed placenta praevia.ย 

A careful speculum examination is useful to look for cervical dilatation, ruptured membranes and investigate for infection.

Typical clinical findings in placental abruption include:

  • Abdominal tenderness: constant pain is consistent with abruption
  • Uterus feels โ€˜woodyโ€™ or โ€˜tenseโ€™ (typical of placental abruption)
  • Signs of shock (if significant haemorrhage): shock out of keeping with visible loss is typical of concealed placental abruption

Fetal wellbeing should be checked with a cardiotocograph (CTG) at 26 weeks gestation or above, otherwise auscultate the fetal heart only.


Differential diagnoses

Possible differential diagnoses in the context of placental abruption include:ย 

  • Placenta praevia: usually painless, bright red bleeding
  • Vasa praevia: where fetal blood vessels run near the internal cervical os (involves the characteristic triad of vaginal bleeding, rupture of membranes and fetal deterioration)
  • Uterine rupture:ย usually occurs in labour with a history of previous caesarean section
  • Early labour can sometimes present with a small amount of bleeding and intermittent abdominal pain
  • Malignant lesions (e.g. carcinoma)
  • Benign lesions (e.g. cervical ectropion): common
  • Infections (e.g. chlamydia)

Investigations

Placental abruption is a clinical diagnosis and there are no sensitive or reliable diagnostic tests available.5

Bedside investigations

Relevantย bedside investigations include:

  • Cardiotocograph (CTG): should be performed in women above 26 weeks gestation to assess fetal wellbeing. Abruption can result in fetal hypoxia and abnormalities of the fetal heart rate pattern. Under 26 weeks handheld doppler or USS should be performed to assess for a fetal heartbeat.

Laboratory investigations

Relevantย laboratory investigations include:

  • FBC, U&Es, LFTs: baseline blood tests
  • Group and save/crossmatch: if large volumes of blood loss patient may require transfusion
  • Clotting profile: important in the context of bleeding
  • Kleihauer test: required if the woman is resus negative

Imaging

Relevant imaging investigations include:

  • Ultrasound: women presenting with antepartum haemorrhage should have an ultrasound scan performed to confirm or exclude placenta praevia if the placental site is not already known. Ultrasound has limited sensitivity in the identification of retroplacental haemorrhage.ย 

Management

Management of anย antepartum haemorrhage due to placental abruption includes a rapid ABCDE assessment and resuscitation. Maternal resuscitation should not be delayed to determine fetal viability.

Definitive management depends on the gestation and presence of fetal distress:

  • Fetal distress: emergency caesarean section
  • No fetal distress < 36 weeks: observe closely, steroids, no tocolysis, gestational age determines delivery
  • No fetal distress >36 weeks: deliver vaginally

In cases of in-utero fetal death, induced vaginal delivery or caesarean section may be indicated due to maternal compromise.

In all cases, anti-D should be administered within 72 hours of the onset of bleeding if the woman is rhesus D negative.


Complications

Maternal complications of placental abruption include:

Fetal complicationsย of placental abruption include:

Prognosis

Placental abruption is associated with a high perinatal mortality rate and is responsible for 15% of perinatal deaths.


Key points

  • Placental abruption is defined as premature separation of a normally sited placenta from the uterine wall.
  • The typical clinical presentation is sudden onset constant pain +/- dark red bleeding depending on whether the abruption is concealed (bleeding remains within the uterus and is not visible) or revealed (visible vaginal bleeding).
  • Risk factors include past placental abruption, pre-eclampsia, advanced age, multiparity, low maternal BMI, assisted reproductive techniques, smoking, cocaine and endometriosis.
  • Possible clinical findings include shock, abdominal tenderness, uterus feeling โ€˜woodyโ€™ or โ€˜tenseโ€™, fetal distress and vaginal bleeding.
  • Placental abruption is a clinical diagnosis and there are no sensitive or reliable diagnostic tests available.
  • Management involves A-to-E assessment. If fetal distress is present, then an immediate caesarean section should be performed. If no fetal distress and <36 weeks observe closely, steroids, no tocolysis, delivery depends on gestation. If >36 weeks (without fetal distress) aim for vaginal delivery.
  • Maternal complications include PPH, blood clotting problems and organ dysfunction.
  • Fetal complications include IUGR, hypoxia, premature birth and stillbirth.

Reviewer

Dr Rachel Greenwood

Obstetrics & Gynaecology Registrar


Editor

Dr Chris Jefferies


References

  1. Ananth CV, Keyes KM, Hamilton A, et al. An international contrast of rates of placental abruption: an age-period-cohort analysis. PLoS One. 2015 May 27;10(5):e0125246.
  2. Tikkanen M. Placental abruption: epidemiology, risk factors and consequences. Acta Obstet Gynecol Scand. 2011 Feb;90(2):140-9.
  3. Blausen. Placental abruption concealed vs. revealed. WikiJournal of Medicine. Licence: [CC BY]
  4. Pariente G, Wiznitzer A, Sergienko R, Mazor M, Holcberg G, Sheiner E. Placental abruption: critical analysis of risk factors and perinatal outcomes. Journal of Maternal, Fetal and Neonatal Medicine. 2010;24:698โ€“702.
  5. RCOG. Antepartum Haemorrhage. Green-top Guideline No.63. Nov 2011. Page 8. Available from: [LINK]

 

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