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This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
The Bottom Line
- Premature separation of normally sited placenta. Incidence ~1% of pregnancies
- Presentation: painful dark vaginal bleeding + rigid "woody" tender uterus + fetal distress
- Concealed haemorrhage (20%): no visible bleeding but maternal shock — clinical picture worse than apparent blood loss
- Risk factors: pre-eclampsia, previous abruption, smoking, cocaine use, trauma, PPROM
- Diagnosis is CLINICAL — USS unreliable (only ~50% sensitivity)
- Complications: DIC (most feared), maternal shock, fetal death, renal failure
Overview
Placental abruption is the partial or complete separation of a normally implanted placenta from the uterine wall before delivery of the fetus. It is a significant obstetric emergency and a leading cause of APH. Haemorrhage may be revealed (visible vaginal bleeding), concealed (blood trapped behind the placenta), or mixed. Concealed abruption is particularly dangerous as the degree of shock is out of proportion to visible blood loss. Abruption can trigger DIC through the release of thromboplastins from the placental site into the maternal circulation.
Epidemiology
Placental abruption occurs in approximately 0.5–1% of pregnancies and accounts for ~30% of APH cases. The recurrence risk in subsequent pregnancies is 6–17%. The strongest risk factor is pre-eclampsia. Other risk factors include previous abruption, chronic hypertension, smoking, cocaine or amphetamine use, abdominal trauma, PPROM, polyhydramnios, advanced maternal age, multiparity, and thrombophilia.
Clinical Features
Symptoms
Sudden-onset constant abdominal pain — often severe
Vaginal bleeding — typically dark red, but may be absent in concealed abruption
Uterine tightening and contractions
Reduced or absent fetal movements
Symptoms of shock: dizziness, syncope, collapse (may precede visible bleeding)
Back pain (posterior placenta)
Signs
Woody hard, tender uterus (tonic contraction from myometrial infiltration)
Uterus larger than expected (from concealed blood)
Tachycardia and hypotension — may indicate concealed haemorrhage
Abnormal CTG — fetal bradycardia, late decelerations, or absent fetal heart sounds
High uterine tone — difficult to palpate fetal parts
Investigations
First-line
Clinical assessmentAbruption is a CLINICAL diagnosis. Do not delay treatment for investigations
FBC, coagulation screen, fibrinogenUrgent — fibrinogen <200 mg/dL suggests DIC. Monitor serially
Crossmatch4–6 units. O-negative blood if critical haemorrhage before crossmatch available
CTGContinuous fetal monitoring — fetal distress or intrauterine death
Second-line
UltrasoundMay show retroplacental clot, but sensitivity only ~50%. A normal USS does NOT exclude abruption
Kleihauer testQuantify fetomaternal haemorrhage — guides anti-D dosing in Rh-negative women
U&Es, LFTsAssess for renal impairment and hepatic dysfunction
Specialist
Thromboelastography (TEG/ROTEM)Point-of-care coagulation testing if DIC suspected — guides blood product replacement
1
Resuscitation
- A-E approach. Two large-bore IV cannulae. Aggressive fluid resuscitation
- Urgent bloods: FBC, coagulation, crossmatch, fibrinogen
- Activate major obstetric haemorrhage protocol if massive
- Involve consultant obstetrician, anaesthetist, haematologist, neonatal team
2
Fetus alive — with fetal compromise
- Emergency caesarean section — category 1 (within 30 minutes)
- Correct coagulopathy with blood products (FFP, cryoprecipitate, platelets) before/during surgery
- Betamethasone if time allows and <34 weeks
3
Fetus alive — no fetal compromise
- If preterm and mild abruption with settled bleeding: conservative management, admit, serial FBC and coagulation
- Antenatal corticosteroids if <34 weeks
- Plan delivery — timing depends on gestation and ongoing stability
- If at term with stable abruption: consider induction of labour with continuous CTG
4
Intrauterine fetal death
- Aim for vaginal delivery if maternal condition is stable — induce labour
- Correct coagulopathy aggressively (DIC common with major abruption and fetal death)
- Caesarean section only if maternal indication (uncontrollable haemorrhage, failed induction)
Complications
- DIC: Most feared complication — consumptive coagulopathy from thromboplastin release. Monitor fibrinogen (aim >200 mg/dL)
- Maternal shock: Hypovolaemic shock from concealed or revealed haemorrhage
- Renal failure: Acute tubular necrosis from hypovolaemia and DIC
- Couvelaire uterus: Myometrial infiltration with blood — may lead to postpartum atony and need for hysterectomy
- Fetal death: Occurs in 30–50% of clinically significant abruptions
- Sheehan syndrome: Postpartum pituitary necrosis from severe haemorrhagic shock
UKMLA Exam Tips
- 1Abruption = painful, dark blood, woody hard uterus. Praevia = painless, bright red, soft uterus
- 2Concealed abruption: shock out of proportion to visible blood loss — always think of this
- 3USS is unreliable for abruption (~50% sensitivity) — it is a CLINICAL diagnosis
- 4DIC is the major life-threatening complication — check fibrinogen urgently and serially
- 5Fetal death with abruption: aim for vaginal delivery (not CS) unless maternal indication
- 6Cocaine use is a classic exam risk factor for abruption
practicetest your knowledge on placental abruptionApply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — obstetrics and beyond.
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