Amniotic fluid embolism: antepartum, intrapartum and demographic factors.

OBJECTIVE: To describe the incidence, antepartum, intrapartum and postpartum risk factors, and mortality rate of amniotic fluid embolism (AFE).

METHODS: We used 2001-2007 California health discharge data to identify cases of AFE by ICD-9 codes.

RESULTS: Of 3,556,567 deliveries during the time period, we identified 182 cases of AFE, resulting in a population incidence of 5.1 in 100,000. Twenty-four of the cases resulted in death, giving a case fatality rate of 13.2%. Non-Hispanic blacks had a higher than 2-fold odds of developing AFE. AFE increased significantly with maternal age, most significantly after age 39. Cardiac disease had a nearly 70-fold higher association with AFE, cerebrovascular disorders had a 25-fold higher association, while conditions such as eclampsia, renal disease, placenta previa and polyhydramnios had nearly 7- to 13-fold higher associations. Classical cesarean delivery, abruption placentae, dilation and curettage, and amnioinfusion were all procedures highly associated with AFE.

CONCLUSION: Several antepartum and peripartum conditions and procedures are associated with significantly higher risks of amniotic fluid embolism. This information may contribute to a better understanding of the pathophysiology of AFE and potentially help identify those at the highest risk of developing this morbid condition.