Amniotic Fluid Embolism

Amniotic fluid embolism (AFE) is a catastrophic syndrome occurring during labor and delivery or immediately postpartum. Amniotic fluid embolism is an important cause of maternal deaths in developed countries. It has high morbidity and mortality rate. The associated mortality and morbidity have decreased dramatically in recent times, such that recent reported maternal mortality is now in the order of 16%. The true incidence is unclear because this syndrome is difficult to identify and the diagnosis remains one of exclusion, with possible under-reporting of nonfatal cases. The pathophysiology of AFE remains unclear. Amniotic fluid embolism occurs when there is a breach in the barrier between the maternal circulation and amniotic fluid. Two separate life-threatening processes seem to occur either simultaneously or in sequence, namely, cardiorespiratory collapse and coagulopathy. The symptoms of AFE commonly occur during labor and delivery or in the immediate postpartum period. Most cases (80%) occur during labor, but it can occur either before labor (20%) or after delivery. About 25% of patients will die within 1 hour of onset. The classic clinical presentation of AFE is that of sudden onset of dyspnea, respiratory failure and hypotension followed by cardiovascular collapse, disseminated intravascular coagulation and death. AFE is poorly understood and diagnosed largely by exclusion. Presently, the AFE diagnosis is not based on any clinical or laboratory finding. The treatment is still not causative but supportive and focuses initially on rapid maternal cardiopulmonary stabilization. The most important goal of therapy is to prevent additional hypoxia and subsequent end-organ failure. The prognosis and mortality of AFE have improved significantly with early diagnosis of AFE and prompt and early resuscitative measures.