Amniotic fluid embolism: a leading cause of maternal death yet still a medical conundrum

Amniotic fluid embolism is a rare and potentially catastrophic condition that is unique to pregnancy. The presentation may range from relatively subtle clinical events to sudden maternal cardiac arrest. Despite an increased awareness of the condition, it remains a leading cause of maternal mortality. The underlying mechanisms of amniotic fluid embolism are poorly understood, but current theories support an immune-based mechanism which is triggered by potentially small amounts of amniotic fluid gaining access to the maternal circulation. This can result in a wide spectrum of clinical findings, with cardiovascular and haematological disturbances being prominent. The management of a suspected episode of amniotic fluid embolism is generally considered to be supportive, although in centres with specific expertise, echocardiography may assist in guiding management. Whilst outcomes after an episode of amniotic fluid embolism are still concerning, mortality would appear to have decreased in recent times, likely secondary to an improved awareness of the condition, advances in acute care and the inclusion of less severe episodes in case registries.