Placental abruption is the premature partial or complete separation of a normally implanted placenta from the uterine decidua, complicating 0.6%–1.2% of pregnancies and representing a leading cause of third-trimester vaginal bleeding and perinatal mortality. [1-3] It is primarily a clinical diagnosis; ultrasound has a sensitivity of only ~57%, and a normal ultrasound does not exclude abruption. [1][4]
1. History
- Onset and character of bleeding: Quantity, color (typically dark), duration, intermittent vs. continuous; note that bleeding is concealed in ~18% of cases [1]
- Pain: Abdominal pain, back pain, uterine tenderness; ask about sudden onset vs. gradual
- Contractions: Frequency, regularity, and intensity; uterine irritability or hypertonia
- Fetal movement: Decreased or absent fetal movement
- Precipitating events: Trauma (even minor, e.g., MVA, fall), cocaine/methamphetamine use, recent intercourse
- Gestational age and obstetric history: Prior abruption, prior cesarean, preeclampsia history
- Important negatives: Absence of pain (seen in previa), absence of visible bleeding (concealed abruption), no rupture of membranes
2. Alarm Features
- Hemodynamic instability: Tachycardia, hypotension, signs of hemorrhagic shock [1][5]
- Rigid, "board-like" uterus (uterine hypertonia/tetanic contractions)
- Nonreassuring fetal heart rate tracing (late decelerations, bradycardia, sinusoidal pattern)
- Absent fetal heart tones — abruption involving >50% of the placenta is frequently associated with fetal death [3]
- Signs of DIC: Oozing from IV sites, petechiae, mucosal bleeding — DIC occurs in up to 23% of severe (Stage III) abruptions [6-7]
- Couvelaire uterus (uterine apoplexy) — blood infiltrates the myometrium
- Significant hemorrhage can lead to consumptive coagulopathy, renal failure, and maternal death [5][8]
3. Medications
- Relevant contributors: Cocaine, methamphetamines, and other sympathomimetics are strongly associated with abruption [3][9]
- Anticoagulant therapy may worsen hemorrhage in the setting of abruption
- Treatments:
- Antenatal corticosteroids (betamethasone 12 mg IM × 2 doses, 24 hours apart) between 24–34 weeks if delivery is anticipated; can be considered 34 0/7–36 6/7 weeks if not previously given [1]
- RhoGAM (Rho(D) immune globulin) for Rh-negative patients, dosed based on Kleihauer-Betke results [1]
- Oxytocin for labor augmentation if vaginal delivery is planned
- Blood products (pRBCs, FFP, cryoprecipitate, platelets) for hemorrhage and coagulopathy management [8][10]
- Tocolytics are generally contraindicated in acute abruption; however, emerging data suggest atosiban may have a role in selected cases for fetomaternal resuscitation prior to cesarean [11]
4. Diet
- Not directly applicable in the acute setting
- Long-term: Adequate folate intake and avoidance of alcohol may reduce general placental pathology risk
- Hydration is critical during resuscitation
5. Review of Systems
- OB/GYN: Vaginal bleeding, leaking fluid (PPROM), contractions, fetal movement
- GI: Nausea/vomiting (can accompany severe abruption), abdominal pain
- GU: Hematuria (may indicate renal involvement or urinary source of bleeding)
- Heme: Easy bruising, bleeding from gums or IV sites (DIC)
- Neuro: Headache, visual changes, hyperreflexia (preeclampsia overlap)
- Constitutional: Lightheadedness, syncope, diaphoresis (hemorrhagic shock)
6. Collateral History and Family History
- Prior obstetric history: Previous abruption is the single strongest maternal risk factor (AOR 2.72) [9]
- History of hypertensive disorders in prior pregnancies
- Thrombophilia history (personal or family): Factor V Leiden, antiphospholipid syndrome [3]
- Social context: Tobacco use, substance use (cocaine, marijuana), intimate partner violence/trauma [9]
- Collateral from EMS/bystanders: Mechanism and severity of trauma if applicable
7. Risk Factors
A 2025 meta-analysis of 54 studies (>7.2 million pregnancies) identified 58 independent risk factors across three categories: [9]
- Maternal baseline: Previous abruption (AOR 2.72), maternal age ≥35, smoking, cocaine use, low BMI (<18.5), multiparity ≥3, anemia (Hgb <11), prior cesarean, prior stillbirth, ART/IVF, unmarried status
- Pregnancy complications: Placenta previa (AOR 7.31 — strongest overall), preeclampsia, gestational hypertension, PPROM, polyhydramnios, SGA, antepartum hemorrhage [9]
- Other: Abdominal trauma, multifetal gestation, intrauterine infection, cervical incompetence, uterine malformations [3][12]
8. Differential Diagnosis
Pearl: A normal ultrasound does NOT rule out abruption. Fresh retroplacental clot can be isoechoic with the placenta. [1][8]
9. Past Medical History
- Prior abruption — recurrence risk is 5–17% after one episode, up to 25% after two [3]
- Chronic hypertension or preeclampsia
- Thrombophilias (antiphospholipid syndrome, Factor V Leiden)
- Prior cesarean delivery or uterine surgery
- History of PPROM, preterm delivery, or stillbirth
- Substance use disorders (cocaine, tobacco)
10. Physical Exam
- Vital signs: Tachycardia and hypotension suggest significant hemorrhage (may be masked by physiologic hypervolemia of pregnancy) [1]
- Abdominal exam:
- Uterine tenderness (often localized over abruption site)
- Uterine hypertonia — "woody" or "board-like" uterus; high-frequency, low-amplitude contractions
- Fundal height may be increasing (expanding concealed hemorrhage)
- Sterile speculum exam: Assess volume/source of bleeding; rule out cervical/vaginal lesions. Do NOT perform digital cervical exam until previa is excluded [1]
- Fetal assessment: Continuous electronic fetal monitoring — look for late decelerations, decreased variability, bradycardia, or sinusoidal pattern [1-2]
11. Lab Studies
- CBC with serial hemoglobin/hematocrit (may be initially normal due to hemoconcentration)
- Type and screen / crossmatch — prepare for transfusion
- Coagulation panel: PT, PTT, fibrinogen (most sensitive early marker of DIC; levels <200 mg/dL are concerning in pregnancy, where normal is 300–600 mg/dL), D-dimer, FDP [6][10]
- Comprehensive metabolic panel — assess renal function (BUN/Cr), LFTs (rule out HELLP)
- Kleihauer-Betke test — quantify fetomaternal hemorrhage in Rh-negative patients; also useful for assessing severity [1]
- Blood bank notification — ensure availability of pRBCs, FFP, cryoprecipitate, platelets
- Serial labs are essential: even with normal initial fibrinogen, progressive decline can occur rapidly [10]
12. Imaging
- First-line: Transabdominal ultrasound — assess placental location, retroplacental clot, fetal presentation, amniotic fluid volume [1][15]
- Sensitivity is only ~57%; a negative ultrasound does NOT exclude abruption [1]
- Acute clot may be isoechoic with placenta; older clots become more echo-free and easier to detect [8]
- Sonographic findings (retroplacental, subchorionic, intraplacental hematomas) when present are associated with worse outcomes (aOR 8.79 for preterm birth) [16]
- Transvaginal ultrasound is safe and can be performed to evaluate placental location and cervical length [1]
- MRI: Sensitivity approaches 100% for abruption (vs. 52% for ultrasound in one study); consider when US is negative but clinical suspicion remains high and diagnosis would change management [17]
- Imaging should never delay delivery in an unstable patient
13. Special Tests
- Continuous electronic fetal monitoring (EFM): Most important real-time assessment tool; abnormal FHR tracing is the most common finding combined with bleeding (39% of cases) [1]
- Kleihauer-Betke test: Quantifies fetal cells in maternal circulation; guides RhoGAM dosing
- Bedside clot test (Lee-White): If coagulation studies are delayed, draw 5 mL of blood in a red-top tube — failure to clot within 6 minutes or clot dissolution suggests DIC
- DIC scoring systems (e.g., JSOG DIC score) — elevated scores on admission predict need for transfusion [10]
- Staging system (per emergency obstetric care guidelines): [6]
- Stage 0: Asymptomatic (diagnosed retrospectively)
- Stage I: Vaginal bleeding + abdominal pain, no shock or fetal distress
- Stage II: Vaginal bleeding ± maternal shock absent, fetal distress present
- Stage III: Maternal shock, intrauterine fetal demise, coagulopathy (~30%)
14. ECG
- Not a primary diagnostic tool for abruption
- Indications: Obtain ECG if maternal tachycardia, chest pain, or hemodynamic instability to rule out cardiomyopathy, amniotic fluid embolism, or myocardial ischemia from severe hemorrhage
- Sinus tachycardia is the most common finding in hemorrhagic shock
- ST changes may occur with severe anemia/hypovolemia
15. Assessment
Placental abruption is a clinical diagnosis characterized by vaginal bleeding, abdominal pain, uterine hypertonia, and fetal distress — though the classic triad occurs in only ~10% of cases. [1] Severity ranges from mild (incidental finding) to catastrophic (maternal DIC, fetal death). Two-thirds of abruption cases are classified as severe when accounting for maternal, fetal, and neonatal complications. [18]
Key complications to anticipate
- Maternal: Hemorrhagic shock, DIC (up to 23% in Stage III), acute renal failure (tubular or cortical necrosis), need for hysterectomy, maternal death [5][7][18]
- Fetal/Neonatal: Fetal hypoxia/acidosis, IUFD (100% in Stage III), neonatal asphyxia, prematurity-related morbidity [6-7]
16. Treatment Plan
Initial Stabilization
- ABCs; two large-bore IVs; aggressive crystalloid resuscitation
- Activate massive transfusion protocol if hemorrhagic shock is present
- Left lateral decubitus positioning to optimize uterine perfusion
- Continuous EFM
Definitive Management — guided by gestational age, maternal stability, and fetal status: [1][3]
- Term (≥37 weeks) or unstable at any GA: Stabilize and deliver
- Cesarean delivery for fetal distress or maternal instability
- Vaginal delivery is preferred if maternal/fetal status is reassuring and delivery is imminent [1]
- Preterm, stable, resolved bleeding: Expectant management may be considered with MFM consultation; antenatal corticosteroids if 24–34 weeks [1]
- Fetal demise: Vaginal delivery is strongly preferred; cesarean exacerbates coagulopathy risk [1][3]
DIC Management
- Aggressive replacement: cryoprecipitate (target fibrinogen >150–200 mg/dL), FFP, platelets
- Delivery of the fetus and placenta is the definitive treatment for DIC [5]
Blood Products
- ~55% of patients with abruption-related stillbirth require transfusion; 29% of those need ≥10 units [19]
- Minimum 2 units pRBCs should be prepared when abruption severity causes fetal death [8]
17. Disposition
- Admit all patients with suspected or confirmed abruption for continuous monitoring [1]
- ICU/L&D admission for hemodynamic instability, active hemorrhage, DIC, or nonreassuring fetal status
- Transfer to a facility with massive transfusion capability, NICU, and surgical capacity if not available [1]
- Observation (minimum 4 hours) after minor trauma in pregnancy; if no uterine hyperactivity or fetal distress, may consider discharge with close follow-up [1]
- OB/MFM consultation is mandatory for all cases
- Neonatology should be notified for preterm gestations
18. Follow Up / Return Precautions
- If managed expectantly (mild, preterm, stable): Serial ultrasounds, twice-weekly NST/BPP, serial growth scans, serial labs (CBC, coagulation)
- Recurrence counseling: Risk of recurrence in subsequent pregnancies is 5–17% after one episode [3]
- Return precautions: Any vaginal bleeding, abdominal pain, decreased fetal movement, contractions, leaking fluid, lightheadedness, or syncope warrants immediate evaluation
- Postpartum: Monitor for delayed postpartum hemorrhage, anemia, renal function; pathology review of placenta for confirmation
- Future pregnancy planning: Smoking cessation, substance use treatment, blood pressure optimization, early prenatal care, and consideration of low-dose aspirin if preeclampsia risk factors are present [9]
References
1. Late Pregnancy Bleeding. — Yonke N, Gurule FS, Rosenfeld-O'Tool S. American Family Physician. 2025.
2. Placental Abruption: Pathophysiology, Diagnosis, and Management. — Schneider E, Kinzler WL. Clinical Obstetrics and Gynecology. 2025.
3. Placental Abruption. — Oyelese Y, Ananth CV. Obstetrics and Gynecology. 2006.
4. Hemorrhagic Placental Lesions on Ultrasound: A Continuum of Placental Abruption. — Oyelese Y, Litman E, Hecht JL, Hernandez-Andrade E, Kinzler WL. Journal of Perinatal Medicine. 2025.
5. Abruptio Placentae and Disseminated Intravascular Coagulopathy. — Hall DR. Seminars in Perinatology. 2009.
6. Analysis of Maternal Fetal Outcomes and Complete Blood Count Parameters According to the Stages of Placental Abruption: A Retrospective Study. — Sener S, Uysal G, Adiguzel C, Okcu NT. European Journal of Medical Research. 2025.
7. Clinical Analysis and Classification of Placental Abruption. — Qiu Y, Wu L, Xiao Y, Zhang X. The Journal of Maternal-Fetal & Neonatal Medicine : The Official Journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians. 2021.
8. Interventions for Treating Placental Abruption. — Neilson JP. The Cochrane Database of Systematic Reviews. 2003.
9. Independent Risk Factors for Placental Abruption: A Systematic Review and Meta-Analysis. — Chen D, Gao X, Yang T, et al. BMC Pregnancy and Childbirth. 2025.
10. The Indicators for Early Blood Transfusion in Patients With Placental Abruption With Intrauterine Fetal Death: A Retrospective Review. — Sano Y, Kasai M, Shinoda S, Miyagi E, Aoki S. BMC Pregnancy and Childbirth. 2022.
11. Safety and Efficacy of Atosiban for Fetomaternal Resuscitation Following Severe Placental Abruption in Preparation for an Emergency Cesarean Section: A Narrative Review. — Odendaal HJ, Lamont RF. Expert Opinion on Drug Safety. 2026.
12. Epidemiology, Risk Factors, and Perinatal Outcomes of Placental Abruption-Detailed Annual Data and Clinical Perspectives From Polish Tertiary Center. — Bączkowska M, Kosińska-Kaczyńska K, Zgliczyńska M, et al. International Journal of Environmental Research and Public Health. 2022.
13. Society for Maternal-Fetal Medicine (SMFM) Consult Series #44: Management of Bleeding In the Late Preterm Period. — Society for Maternal-Fetal Medicine (SMFM). Electronic address: pubs@smfm.org, Gyamfi-Bannerman C. American Journal of Obstetrics and Gynecology. 2018.
14. Vaginal Bleeding in Pregnancy. — McKennett M, Fullerton JT. American Family Physician. 1995.
15. ACR Appropriateness Criteria® Second and Third Trimester Vaginal Bleeding. — Expert Panel on GYN and OB Imaging, Shipp TD, Poder L, et al. Journal of the American College of Radiology : JACR. 2020.
16. Obstetric and Neonatal Outcomes in Pregnancies Complicated by Placental Abruption With vs. Without Supporting Sonographic Findings- A Retrospective Cohort Study. — Mor L, Erteschik N, Gandelsman E, et al. Placenta. 2024.
17. MR Imaging in the Evaluation of Placental Abruption: Correlation With Sonographic Findings. — Masselli G, Brunelli R, Di Tola M, Anceschi M, Gualdi G. Radiology. 2011.
18. Severe Placental Abruption: Clinical Definition and Associations With Maternal Complications. — Ananth CV, Lavery JA, Vintzileos AM, et al. American Journal of Obstetrics and Gynecology. 2016.
19. Transfusion and Hematologic Indices in Cases of Stillbirth Due to Placental Abruption. — White A, Pruszynski J, Williams R, Duryea EL. American Journal of Obstetrics and Gynecology. 2023.