Amniotic fluid embolism: review

Amniotic fluid embolism is a rare but dreadful syndrome in Obstetrics, which happens, in most of the cases, in the peripartum period. The actual "embolisation" of the pulmonary vessels does not explain the whole picture of the syndrome. An immune mechanism, similar to an anaphylactic reaction, is more convincingly the background of the event, but the pathogenesis is still ill-defined. Similarly the initial symptoms are difficult to interpret and distinguish from other acute and life-threatening emergencies (i.e. pulmonary embolism, placental abruption, septic shock, stroke, myocardial ischemia, etc.), therefore the diagnosis is one of exclusion, very often on postmortem report. Thus the prevalence of the disease is difficult to establish, most of the reports being postmortem cases or National Registries data. These data, based either on autopsy series or on registries, are non representative of the true prevalence of the event and obviously confusing for the correct understanding of the disease process. Risk factors are all those conditions or manouvres, which contemplate a breech in the maternal-fetal barrier. Again, given the rarity of the syndrome, no single event is clearly identifiable as a case-effect risk factor. Prognosis, which is obviously biased by the reporting system, is particularly grim both in terms of survival and morbidity. The symptoms being often elusive at the beginning, but rapidly and progressively catastrophic, a multidisciplinary team approach is warranted in order to provide the best chance of survival both for mother and baby. Immediate and aggressive resuscitation is, therefore, advised whenever a mother in labour or in the early postpartum period experiences a sudden collapse.