An overview of amniotic fluid embolism: Past, present and future directions

Abstract

Objective: A recent report has highlighted that amniotic fluid embolism (AFE) is the first among maternal mortality in Japan. The clinical presentation is not the same with respect to symptoms, timing and subsequent course. Methods: This article reviews the English language literature for pathophysiology on AFE based on the clinical and animal studies. Results: First, AFE syndrome may be divided into three subgroups designated the classical subtype, the anaphylactoid subtype and the DIC subtype, each having a distinct pattern of clinical symptoms and disease severity. Second, AFEassociated reactions can be classified as an anaphylactoid reaction or complement activation to fetal antigens or an idiosyncratic reaction. Host idiosyncrasy may be a major cause of hypersensitivity reaction. Third, the AFE reaction may be caused by a combination of immunologic and vasospastic factors. Finally, the development of effective markers for diagnosing entry of amniotic fluid into the maternal circulation would have an impact on early diagnosis and AFE-related mortality. Conclusion: This review summarizes new insights into the pathophysiology of AFE, with a focus on the potential direction of future research. © Tsunemi et al.