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This is a clinician-written, evidence-based summary aligned to the USMLE Step 2 CK Content Outline. It is intended for medical students preparing for USMLE Step 2 CK. Management reflects current ACC/AHA, USPSTF, and APA guidelines. Always cross-reference with UpToDate, institutional protocols, and clinical judgment.
The Bottom Line
- Classic presentation: painful vaginal bleeding, uterine tenderness, contractions, and nonreassuring fetal tracing
- Bleeding may be concealed; visible blood loss can underestimate severity
- Risk factors include hypertension/preeclampsia, trauma, cocaine, smoking, prior abruption, PROM, and rapid uterine decompression
- Diagnosis is clinical; ultrasound can miss abruption
- Maternal instability or fetal distress at viable gestation requires urgent delivery
Overview
Placental abruption is premature separation before delivery. It compromises maternal hemodynamics and fetal oxygenation and can trigger consumptive coagulopathy. Unlike previa, abruption is typically painful with a tender hypertonic uterus.
Epidemiology
Abruption is a major cause of antepartum hemorrhage, fetal distress, preterm birth, and stillbirth. Chronic hypertension and preeclampsia are major risk factors; cocaine is a classic exam trigger.
Clinical Features
Symptoms
Painful vaginal bleeding after 20 weeks
Constant abdominal or back pain
Frequent contractions or uterine irritability
Decreased fetal movement
Bleeding may be concealed
Signs
Tender firm hypertonic uterus
Nonreassuring fetal tracing or bradycardia
Maternal tachycardia, hypotension, or shock
Oozing from IV sites suggests DIC
Hypertension or preeclampsia may be present
Investigations
First-line
Clinical diagnosisPainful bleeding, uterine tenderness/hypertonicity, and fetal distress drive diagnosis
Continuous fetal monitoringAssess fetal status if viable
CBC, type/crossmatch, coags, fibrinogenLow fibrinogen suggests severe abruption/DIC
Second-line
UltrasoundUseful to rule out previa but limited sensitivity for abruption
Kleihauer-BetkeMay quantify fetomaternal hemorrhage for Rh dosing
Preeclampsia labsAssess concurrent hypertensive disease
Specialist
OB/anesthesia/blood bank activationSevere abruption, DIC, maternal instability, or urgent delivery
Trauma evaluationIf associated with motor vehicle collision or abdominal trauma
1
Immediate management
- Stabilize mother first with left uterine displacement, oxygen as needed, IV access, fluids/blood products
- Continuous fetal monitoring if viable
- Type/crossmatch and correct coagulopathy
- Give Rh(D) immune globulin if Rh-negative and unsensitized
2
Delivery decisions
- Maternal instability or fetal distress at viable gestation: urgent delivery, often cesarean
- Fetal demise: vaginal delivery preferred if mother stable
- Mild stable preterm abruption: inpatient observation may be considered
- Term abruption: delivery is generally recommended
3
Coagulopathy management
- Monitor fibrinogen, PT/aPTT, platelets, and clinical bleeding
- Replace fibrinogen with cryoprecipitate when low and bleeding
- Treat DIC by addressing abruption and supporting coagulation
Complications
- Fetal hypoxia or death: Acute loss of placental exchange
- Hemorrhagic shock: Visible blood may underestimate loss
- DIC: Placental tissue factor triggers coagulopathy
- Couvelaire uterus: Blood extravasation into myometrium with atony risk
- Postpartum hemorrhage: Atony and coagulopathy
USMLE Step 2 CK Exam Tips
- 1Painful third-trimester bleeding + tender uterus = abruption
- 2Painless bleeding + soft uterus = previa
- 3Ultrasound cannot rule out abruption
- 4Cocaine use + acute abdominal pain/bleeding = abruption
- 5Low fibrinogen in antepartum bleeding suggests severe abruption/DIC
- 6Fetal demise with stable mother = vaginal delivery preferred
- 7Concealed abruption may cause shock with little visible bleeding
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