Amniotic fluid embolism: analysis of the national registry.

Abstract

We analyzed the clinical course and investigated possible pathophysiologic mechanisms of amniotic fluid embolism. We carried out a retrospective review of medical records. Forty-six charts were analyzed for 121 separate clinical variables. Amniotic fluid embolism occurred during labor in 70% of the women, after vaginal delivery in 11%, and during cesarean section after delivery of the infant in 19%. No correlation was seen with prolonged labor or oxytocin use. A significant relation was seen between amniotic fluid embolism and male fetal sex. Forty-one percent of patients gave a history of allergy or atopy. Maternal mortality was 61%, with neurologically intact survival seen in 15% of women. Of fetuses in utero at the time of the event, only 39% survived. Clinical and hemodynamic manifestations were similar to those manifest in anaphylaxis and septic shock. Intact maternal or fetal survival with amniotic fluid embolism is rare. The striking similarities between clinical and hemodynamic findings in amniotic fluid embolism and both anaphylaxis and septic shock suggest a common pathophysiologic mechanism for all these conditions. Thus the term amniotic fluid embolism appears to be a misnomer.