Poster Session I Thursday, February 14 • 10:45 AM - 12:00 PM • Octavius Ballroom • Caesars Palace| Volume 220, ISSUE 1, SUPPLEMENT , S101-S102, January 01, 2019

130: The prevalence of placenta previa in pregnancies complicated by amniotic fluid embolism


      The AFE foundation in collaboration with Baylor College of Medicine has established an international AFE registry, using recently published diagnostic criteria for research reporting (Clark SL,2016 AJOG). Given the theory of potential placental or fetal debris entering maternal circulation as a cause of AFE, we sought to investigate the relationship between abnormal placentation and occurrence of AFE.

      Study Design

      Charts of patients enrolled in the AFE registry between 2013 and 2017 were abstracted and women were classified as having AFE, unlikely to have an AFE, or indeterminate. Indeterminate cases were defined as those with incomplete records, or whose diagnosis remained uncertain after review.


      Of 145 currently enrolled patients, 115 had records available for review. Fifty-nine percent (68/115) were determined to have suffered an AFE, while 23% (26/115) were probable non-AFE, and 18% (21/115) were indeterminate. Seven percent (5/68) of women with an AFE had a placenta previa during the index pregnancy, compared to the established historical prevalence of 5 per 1,000 births (0.5%). This represents a 15-fold increase in the prevalence of placenta previa in women with AFE.


      Administrative databases proposed various risk factors for AFE, but are hampered by misdiagnoses in a substantial proportion of cases. In our study, using strict criteria for AFE diagnosis, we identified placenta previa as a risk factor. Our data suggests that abnormal placentation, vis-à-vis placenta previa, may be an independent risk factor in the pathophysiology of AFE.