Placental Abruption: Risk Factors & Classification

• Placental abruption: premature separation of the placenta from the uterus before fetal delivery.
• Placental abruption is a significant cause of maternal and fetal morbidity and mortality.
• Placental abruption occurs in approximately 1% of all pregnancies.

Risk Factors

• Maternal hypertension is the most common risk factor.
• Previous placental abruption.
• Trauma (e.g., motor vehicle accident).
• Cocaine or tobacco use.
• Advanced maternal age.
• Multiparity.
• Uterine overdistension (e.g., multiple gestation, polyhydramnios).
• Thrombophilias.
• Chorioamnionitis.
• Premature rupture of membranes.
• Short umbilical cord.
• Uterine fibroids (especially if located behind the placenta).

Classification Based on Severity

• Grade 1 (Mild): represents about 48% of cases
  • Minimal vaginal bleeding.
  • No fetal distress.
  • Stable maternal vital signs.
• Grade 2 (Moderate): represents about 27% of cases.
  • Mild to moderate vaginal bleeding.
  • Possible uterine tenderness.
  • Possible fetal heart rate abnormalities.
  • Maternal vital signs may show compromise (e.g., tachycardia).
• Grade 3 (Severe): represents about 24% of cases.
  • Moderate to severe vaginal bleeding or concealed hemorrhage.
  • Uterine tenderness is common.
  • Fetal distress or demise is common.
  • Maternal vital signs often unstable (e.g., hypotension, coagulopathy).

Pathophysiology

• Hemorrhage into the decidua basalis leads to placental separation.
• Separation may be partial or complete, concealed (internal) or revealed (external).
• Hemorrhage can dissect between myometrial fibers, leading to a Couvelaire uterus (myometrial bleeding).

Clinical Presentation

• Presentation can vary widely.
• Vaginal bleeding is present in 80% of cases, but may be concealed.
• Abdominal pain often has a sudden onset.
• Uterine contractions may be frequent and of low intensity.
• Uterine tenderness.
• Fetal distress (e.g., abnormal heart rate tracing).
• Preterm labor.
• Maternal shock in severe cases.

Diagnosis

• Primarily clinical, based on signs and symptoms.
• Ultrasound may be helpful, but a negative result does not rule out abruption.

Laboratory Studies

• Complete blood count (CBC) to assess for anemia and thrombocytopenia.
• Coagulation studies (PT, PTT, fibrinogen) to assess for DIC.
• Type and crossmatch for possible transfusion.
• Kleihauer-Betke test to assess for fetal-maternal hemorrhage (not diagnostic).

Differential Diagnosis

• Placenta previa.
• Vasa previa.
• Uterine rupture.
• Preterm labor.
• Abdominal pain from other causes (e.g., appendicitis, ectopic pregnancy).

Management

• Depends on the severity of the abruption and gestational age.

General Management Principles

• Stabilize the mother:
  • Establish intravenous access.
  • Monitor vital signs.
  • Assess blood loss.
  • Administer blood products as needed.
• Assess fetal status:
  • Continuous fetal heart rate monitoring.
  • Biophysical profile (BPP) if the fetus is viable but not in extremis.

Delivery Indications

• Severe abruption.
• Fetal distress.
• Maternal instability.

Mode of Delivery

• Vaginal delivery: considered if abruption is mild, fetus is not in distress, and labor is progressing rapidly.
• Cesarean delivery: generally indicated for severe abruptions, fetal distress, or maternal instability.

Preterm Labor Management

• Mild abruption and preterm fetus: expectant management may be considered.
  • Close monitoring of mother and fetus.
  • Tocolytics to inhibit contractions (controversial and typically avoided in significant abruptions).
  • Corticosteroids to promote fetal lung maturity.

Management of Complications

• Disseminated intravascular coagulation (DIC): treat with blood products and address abruption.
• Hypovolemic shock: treat with intravenous fluids and blood products.
• Renal failure: monitor fluid balance and consider dialysis if necessary.
• Maternal death: requires prompt resuscitation and delivery of the fetus if possible.
• Fetal death: delivery is indicated to prevent maternal complications.

Potential Maternal Complications

• Hemorrhagic shock.
• Disseminated intravascular coagulation (DIC).
• Couvelaire uterus (uterine atony).
• Renal failure.
• Postpartum hemorrhage.
• Hysterectomy (rare, but may be necessary to control bleeding).
• Maternal death.

Potential Fetal Complications

• Preterm birth.
• Hypoxia.
• Anemia.
• Growth restriction.
• Fetal death.

Prevention Strategies

• Management of maternal hypertension.
• Abstinence from smoking and cocaine.
• Counseling about risks of trauma.
• Identification and management of thrombophilias.

Recurrence Risk

• Women with a history of placental abruption have a 5%-15% increased risk of recurrence in subsequent pregnancies.
• Close monitoring is warranted in subsequent pregnancies.

Long-Term Considerations

• Women who have experienced placental abruption are at increased risk for cardiovascular disease later in life.
• Follow-up with a physician is recommended to monitor for risk factors and implement preventive strategies.

Overview of placental abruption, a condition where the placenta separates from the uterus prematurely. Includes risk factors such as hypertension and trauma. Covers classification based on severity (Grade 1, Grade 2).