Amniotic fluid embolism. Three case reports with a review of the literature.

Amniotic fluid embolism is a catastrophic event of the intra- and early postpartum period which may also be seen with cesarean delivery and during abortions. Presenting symptomatology includes respiratory distress with cyanosis, shock, and possibly tonic-clonic seizures. DIC frequently occurs. The pathogenesis may include entry of amniotic fluid through lacerations or ruptures of the uterus or cervix, through endocervical veins and through abnormal uteroplacental sites, such as with placental abruption, placenta previa, or placenta accreta. Amniotic fluid probably causes cardiovascular-respiratory symptoms by pulmonary vascular obstruction and through a vasoactive substance causing pulmonary vascular constriction. The lethality of amniotic fluid may be enhanced by a high particulate content or meconium staining. The diagnosis of amniotic fluid embolism may be made ante mortem by demonstrating amniotic fluid debris in central blood samples or expectorated sputum. Postmortem diagnosis often requires meticulous examination of the pulmonary microvasculature with the utilization of special stains. Treatment is directed towards symptoms of shock, arterial hypoxemia, and DIC. Acute renal failure may complicate the picture after shock. If the patient survives the embolic and coagulative problems, recovery is usually complete without long-term sequelae.