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Amniotic Fluid Embolism

Research Questions

  • What is the current incidence of amniotic fluid embolism in the UK?
  • What are the risk factors for AFE in the UK?
  • How is AFE managed in the UK?
  • What are the outcomes for both mother and infant of AFE in the UK?


Amniotic fluid embolism (AFE) has been identified by the UK Confidential Enquiry into Maternal Deaths as a leading cause of maternal mortality with some evidence that fatality is decreasing in the UK. Estimates of incidence vary between 1 in 8000 and 1 in 80,000 pregnancies[1]. Estimates of the mortality rate from this condition also vary widely[2], from as much as 86% to more recent estimates of 16-30%. No clear risk factors are identifiable from previous cases, but some preliminary evidence suggests that earlier diagnosis may lead to better outcomes[3]. A wide range of treatments have been described in case reports[2], but there has been no comprehensive study of the epidemiology and management of this condition in the UK.

A database of voluntary notifications has been established in the UK to collect information on epidemiology and management[3]. The incorporation of this study into the national obstetric surveillance system will improve ascertainment and allow a comprehensive study of the epidemiology and current management.

Case Definition

The cases will be all women in the UK identified as having amniotic fluid embolism using the following definition:

EITHER a clinical diagnosis of AFE (acute hypotension or cardiac arrest, acute hypoxia or coagulopathy in the absence of any other potential explanation for the symptoms and signs observed)

OR a pathological diagnosis (presence of fetal squames or hair in the lungs).

Study Size

The study will run initially for three years. On the basis of data from the voluntary register, the study may expect to identify up to 10 cases over a one year period2. The study will therefore aim to collect data on 30 cases over three years.

Download the Data Collection Form (DCF)

UKOSS Amniotic Fluid Embolism DCF


  1. ^ Gilbert WM, Danielsen B. Amniotic fluid embolism: decreased mortality in a population-based study. Obstet Gynecol 1999; 93(6):973-7.
  2. a, b Tuffnell DJ. Amniotic Fluid Embolism. Current Opinion in Obstetrics and Gynaecology 2003; 15:119-22.
  3. a, b Tuffnell DJ. Amniotic Fluid Embolism. Maternal Morbidity and Mortality. London: RCOG, 2002.

Updated: Tuesday, 17 January 2023 17:50 (v9)