Key Facts

Placental abruption is the premature separation of a normally implanted placenta from the uterine wall before delivery of the fetus. It is a major cause of antepartum haemorrhage and is associated with significant maternal and perinatal morbidity and mortality.

Epidemiology

• Incidence: approximately 1% of all pregnancies
• Responsible for 30% of cases of APH
• Leading cause of antepartum stillbirth in the UK
• More common in the third trimester but can occur from 20 weeks

Aetiology

• Pre-eclampsia/hypertension (strongest association)
• Previous placental abruption (recurrence risk 6-17%)
• Cigarette smoking (dose-dependent, 2× risk)
• Cocaine use (5× risk)
• Abdominal trauma (RTC, domestic violence)
• Preterm premature rupture of membranes
• Multiple pregnancy
• Polyhydramnios (sudden decompression)
• Thrombophilia (antiphospholipid syndrome, factor V Leiden)
• Advanced maternal age, high parity

Pathophysiology

• Rupture of maternal decidual spiral arteries causes bleeding into the decidua basalis
• Blood tracks between the placenta and uterine wall, causing separation
• Revealed haemorrhage: blood tracks down to cervical os and is visible
• Concealed haemorrhage: blood is trapped behind the placenta with no vaginal loss (more dangerous)
• Couvelaire uterus: severe extravasation of blood into the myometrium causing a blue/purple discolouration

Typical Presentation

• Constant abdominal pain (unlike the intermittent pain of contractions)
• Vaginal bleeding (may be absent in concealed abruption)
• Woody hard, tender uterus on palpation
• Uterine irritability with high-frequency contractions
• Signs of maternal shock (tachycardia, hypotension) - may be disproportionate to visible blood loss

Classification by Severity

• Mild: small revealed bleed, minimal pain, no fetal compromise
• Moderate: moderate bleeding and pain, some fetal compromise
• Severe: massive haemorrhage, coagulopathy, fetal death

Red Flags

• Concealed haemorrhage (shock without proportionate vaginal bleeding)
• Fetal bradycardia or absent heart sounds
• DIC (widespread oozing, petechiae)
• Couvelaire uterus
• Oliguria/anuria
• Rapidly increasing uterine size (concealed blood accumulation)

Bedside

• ABCDE assessment
• Continuous CTG (pathological trace with abruption: late decelerations, reduced variability, sinusoidal pattern)
• Blood pressure, pulse (every 15 minutes)
• Fluid balance chart
• Speculum examination (do not perform digital VE until praevia excluded)

Bloods

• FBC (urgent haemoglobin and platelet count)
• Coagulation screen: PT, APTT, fibrinogen (fibrinogen <2 g/L is concerning; <1 g/L indicates severe DIC)
• Crossmatch (minimum 4-6 units in severe cases)
• Kleihauer test (RhD-negative women)
• U&Es (renal function)
• LFTs (if pre-eclampsia suspected)

Imaging

• Ultrasound: may show retroplacental clot but USS has poor sensitivity for abruption (negative scan does not exclude it)
• Diagnosis is primarily clinical

Special Tests

• Thrombophilia screen after acute episode resolves (if recurrent abruption)
• Placental histology postpartum

Non-pharmacological

• ABCDE approach with aggressive resuscitation
• Two large-bore IV cannulae (14-16G)
• Activate major obstetric haemorrhage protocol if severe
• Left lateral position
• Continuous CTG
• Senior obstetric and anaesthetic involvement

Pharmacological

• IV fluid resuscitation: crystalloid initially, then blood products
• Blood products: packed red cells, FFP, platelets, cryoprecipitate as guided by coagulation results (target fibrinogen >2 g/L)
• Anti-D immunoglobulin for RhD-negative women
• Antenatal corticosteroids if <34+6 weeks and delivery can be delayed safely
• Tranexamic acid 1g IV in major haemorrhage
• DO NOT delay delivery for corticosteroids if maternal or fetal compromise

Surgical/Interventional

• Mild abruption at term: induce labour with artificial ROM and oxytocin if CTG reassuring
• Moderate-severe abruption: emergency caesarean section (category 1)
• Intrauterine fetal death: aim for vaginal delivery if maternal condition allows; ensure coagulopathy corrected
• Postpartum: active management of third stage, uterotonic agents
• B-Lynch suture, balloon tamponade, or hysterectomy for refractory PPH

Referral Criteria

• All suspected abruptions require immediate hospital assessment
• Consultant obstetrician must be informed
• Haematology input for DIC
• Subsequent pregnancy: consultant-led care, serial growth scans

• Perinatal mortality: 15-30% overall; up to 50% in severe cases
• Maternal mortality: <1% in developed countries
• DIC complicates 10-30% of significant abruptions
• Renal failure: 1-3% of severe cases
• Recurrence risk: 6-17% after one abruption; 25% after two
• Associated with long-term increased cardiovascular risk in the mother
• Surviving neonates at risk of prematurity-related morbidity

Abruption Severity Classification

DIC Management Targets