Amniotic Fluid Embolism
Anaphylactoid Syndrome of Pregnancy

General Considerations

• Rare and frequently fatal obstetrical emergency occurring in the mother most often during labor resulting in profound hypotension and dyspnea
• Believed to be due to amniotic fluid, fetal cells and unknown substance(s) that are released into the maternal bloodstream due to a breach in the barrier between amniotic fluid and the maternal circulation
  • Such material is not found in the maternal circulation of all patients with the syndrome and many patients with out the syndrome have such materials recovered
• Leads to an anaphylactoid reaction possibly mediated by the complement cascade
• Not predictable and, as yet, not preventable
• May be associated with (although there are many cases in which none of these factors is present)
  • Prolonged labor
• Multiparity
• Male fetus
• Placenta abruptio or previa
• C-section
• Medical induction of labor 

Clinical 

• Acute onset during or immediately following labor of profound hypotension and shortness of breath
• Cough and cyanosis
• Seizures
• Massive disseminated intravascular coagulopathy (DIC) and hemorrhage in up to 50% who survive cardiovascular insult
• Cardiac arrest
• No definitive test
  • Diagnosis of exclusion
• DDX includes massive aspiration
• Pulmonary emboli
• Pulmonary edema from acute myocardial infarction or transfusion reaction 

Imaging 

• Chest radiographs usually (70%) show pulmonary edema, frequently of the non-cardiogenic variety, not specific for this entity
• Chest radiographs can be normal 

Treatment 

• Supportive, includes oxygen
• Hypotension with volume loading, vasopressors and/or inotropes
• Treat coagulopathy FFP and platelets, hemorrhage with packed red blood cells
• Intravenous steroids have been used
• Hemodialysis, intra-aortic balloon pump have been used 

Prognosis 

• Maternal mortality is as high as 60%
• Infant survival rate is 70-80%
• Of those who survive the initial episode of  respiratory distress and hypotension, half develop coagulopathy 

Amniotic fluid embolism. Frontal view of the chest using the portable technique
demonstrates diffuse bilateral airspace disease without pleural fluid. This patient went into acute pulmonary edema during labor and was thought to have amniotic fluid embolism. She and the child survived.
For additional information about this disease, click on this icon if seen above.
For this same photo without the arrows, click here

Moore, Lisa eMedicine  Amniotic Fluid Embolism 

Kian-Hian Tan, Yen-Yen Sim, Jen W. Chiu, Chee-Chuen Loo, Seow-Woon Yeo: Maternal-fetal Survival Following Amniotic Fluid Embolism: 2 Case Reports. The Internet Journal of Anesthesiology. 2002. Volume 5 Number 4