United Kingdom Amniotic Fluid Embolism Register

OBJECTIVE: The United Kingdom Amniotic Fluid Embolism Register was established to identify the incidence of the condition and examine any differences or common factors between survivors and fatalities. DESIGN: An anonymous voluntary register. SETTING: The United Kingdom from 1997 to 2004. POPULATION: Any woman with a clinical diagnosis of amniotic fluid embolism. The entry criteria were as follows: acute hypotension or cardiac arrest, acute hypoxia and coagulopathy with onset during labour, caesarean section or within 30 minutes of delivery with no other clinical condition or potential explanation for the symptoms and signs. METHODS: A data collection form was completed after reporting. MAIN OUTCOME MEASURES: Mortality and morbidity rates in women and their babies. RESULTS: Of 66 cases, 44 had sufficient information to be included. Thirteen (29.5%; 95% CI 17-45%) women died. If the five extra deaths in the Confidential Enquiry into Maternal Death were included, the mortality would be 37% (95% CI 23-52%). Of the 31 survivors, 12 women had a cardiac arrest, 7 had a hysterectomy, 2 had further laparotomies, 1 had subglottic stenosis and 2 had persisting neurological impairment. Twenty-four of the 31 survivors were admitted to intensive care units. Of the 13 women who died, 7 of their babies survived. Four were acidotic at birth, of whom two developed hypoxic ischaemic encephalopathy (HIE) and one of these is known to have developed cerebral palsy. In 18 cases, the woman survived and the baby was alive and in utero at the time of the maternal collapse. Four of these died, four had HIE with one known to have developed cerebral palsy and one other was acidotic at birth. CONCLUSION: The mortality of amniotic fluid embolism is high but the majority of women will survive. There is significant maternal and neonatal morbidity even when the woman survives. Continuing assessment of cases of amniotic fluid embolism is important to identify ways of improving outcome.