Symptoms of Abruptio Placenta
Abruptio placenta classically presents with painful vaginal bleeding (typically dark blood), abdominal pain, and uterine contractions, distinguishing it from the painless bleeding of placenta previa. 1, 2
Cardinal Clinical Features
The diagnosis of placental abruption is primarily clinical, based on the following characteristic presentation:
Classic Triad
- Vaginal bleeding with dark blood - occurs in the majority of cases, though bleeding may be concealed in some instances 2, 3, 4
- Abdominal pain - a hallmark feature that differentiates abruption from placenta previa 1, 2, 5
- Uterine contractions and tenderness - the uterus is typically tender and may be hypertonic 2, 4, 5
Additional Clinical Manifestations
- Abnormal fetal heart rate patterns - ranging from tachycardia to bradycardia or absent fetal heart tones, depending on severity 3, 5
- Uterine hypertonicity - the uterus may feel firm or "board-like" on palpation 4, 5
- Maternal hemodynamic instability - in severe cases, presenting with shock disproportionate to visible blood loss due to concealed hemorrhage 2, 4
Important Clinical Pitfall: Atypical Presentations
Not all abruptions present with pain. Posteriorly inserted fundal placental abruptions can present as "painless abruption" characterized by vaginal bleeding with backache and a non-tender uterus, which can lead to delayed diagnosis and high fetal mortality if unrecognized 6. This atypical presentation mimics placenta previa and requires high clinical suspicion.
Severity-Dependent Features
The clinical presentation varies significantly with severity:
- Mild abruption - may escape clinical detection with minimal bleeding and discomfort 2
- Moderate to severe abruption - presents with the classic triad plus signs of fetal compromise 3, 4
- Severe abruption (>50% placental separation) - frequently associated with fetal death, maternal shock, disseminated intravascular coagulopathy, and renal failure 2, 4
Diagnostic Limitations
Ultrasonography has limited sensitivity for diagnosing abruption - the diagnosis remains clinical, as ultrasound may be negative even in significant abruptions 4. The Kleihauer-Betke test similarly has limited diagnostic value 4. When ultrasound is performed, it may show retroplacental hematoma, but absence of sonographic findings does not exclude the diagnosis 3, 5.