Definition

Key History

• 2^nd or 3^rd trimester vaginal bleeding – may be dark, red or mixed with amniotic fluid (80%)
• Abdominal pain or back pain (70%)

Key Physical Exam

Risk Factors for Placental Abruption

• Abdominal trauma – up to 9.4% of cases
• Cocaine use
• Prior history of abruption
• Hypertension – 2^nd most frequent cause; present in 44% of cases
• Increasing maternal age
• Thrombotic disorders
• Vasculitis
• Vascular disorders

Classification Systems

Differential Diagnosis

Diagnostic Testing

The recommended diagnostic tests for placental abruption include a combination of clinical evaluation, laboratory tests, and imaging studies:

Clinical Evaluation: The diagnosis is primarily clinical, based on symptoms such as abdominal pain, uterine tenderness, uterine contractions or hypertonicity, vaginal bleeding, and atypical or abnormal electronic fetal monitoring (EFM) tracing.

Ultrasound (US): While transabdominal ultrasound is the preferred initial imaging modality, its sensitivity for detecting placental abruption is limited. Specific sonographic findings, such as a retroplacental hematoma, are seen in only 2% to 25% of cases. Therefore, a negative ultrasound does not rule out abruption.

Magnetic Resonance Imaging (MRI): MRI has shown higher sensitivity and specificity compared to ultrasound for diagnosing placental abruption. It can accurately depict placental abruption and should be considered when ultrasound findings are negative but clinical suspicion remains high.

Laboratory Tests: Routine laboratory parameters such as complete blood count (CBC), coagulation profile, and fibrinogen levels are essential to assess the extent of maternal bleeding and coagulation status. Elevated C-reactive protein (CRP) levels have been associated with placental abruption, although they are not specific.

In summary, the diagnosis of placental abruption relies on a combination of clinical evaluation, ultrasound and MRI when necessary, along with laboratory tests to assess maternal and fetal well-being. The American College of Radiology recommends transabdominal ultrasound as the initial imaging modality, with MRI as an adjunct in specific cases.

Clinical Risk and Safety Pearls

• Consider abruption for every patient in premature labor.
• Absence of vaginal bleeding DOES NOT exclude placental abruption.
• Normal ultrasound findings DO NOT exclude placental abruption.
• Incidence is 1% of all deliveries. If there was a prior episode of abruption, the risk rises to 15%; if more than 2, prior episode risk is 25%.
• Placental abruption may be retroplacental, behind the placenta, and have no vaginal bleeding.
• Abruption associated with trauma carries a 30%-70% fetal mortality and a 1% maternal mortality.
• May be associated with preeclampsia, DIC, hypertension, postpartum hemorrhage, and maternal or fetal end organ damage from hypoperfusion (acute renal failure).
• DIC complicates 10% of abruptions.
• Blood volume is increased in pregnancy; therefore, volume lost may exceed 30% before signs of shock or hypovolemia present. Vital signs may be preserved even with significant blood loss.
• In cases of trauma, monitor patient at least 4 hours for evidence of fetal insult, abruption, and/or fetal-maternal transfusion.
• 50% of abruptions occur before 36 weeks gestation.

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Treatment

The treatment for placental abruption is highly individualized and depends on the severity of the abruption, the gestational age, and the maternal and fetal status.

Immediate Management:

• Stabilization: Initial management focuses on stabilizing the mother, including intravenous fluid resuscitation and blood transfusions if necessary, especially in cases of significant hemorrhage or coagulopathy.
• Monitoring: Continuous fetal monitoring and frequent maternal vital signs assessment are crucial to detect any signs of fetal or maternal compromise.

Delivery:

• Term or Near-Term Gestation: If the pregnancy is at or near term and both maternal and fetal conditions are stable, vaginal delivery may be attempted. Induction or augmentation of labor can be considered.
• Fetal or Maternal Compromise: In cases of fetal distress or maternal instability, prompt delivery by cesarean section is indicated to optimize outcomes.
• Fetal Demise: If fetal demise has occurred, vaginal delivery is generally preferred unless there are other obstetric indications for cesarean section.

Conservative Management:

• Preterm Gestation: For stable patients with preterm gestation, conservative management with close monitoring may be appropriate. This includes hospitalization, bed rest, and corticosteroids to enhance fetal lung maturity if the gestation is less than 34 weeks.

Management of Complications:

• Coagulopathy: Aggressive management of disseminated intravascular coagulation (DIC) and other coagulation abnormalities is essential. This may involve the administration of blood products such as fresh frozen plasma, platelets and cryoprecipitate.

Complications

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