Is the incidence of amniotic fluid embolism rising?

From February 2005 to February 2009, Knight and associates identified a total of 60 cases of AFE in the UK Obstetric Surveillance System. Their analysis of these cases, along with the cases of 1,227 women in the control group, is a valuable contribution to our understanding of AFE—an entity that few obstetricians will have the occasion to manage in their professional careers. One of the strengths of the study is the use of a comprehensive database, which made it possible to exclude 26 additional cases originally diagnosed as AFE but determined to be another entity. Scrutiny of these cases suggests that AFE may be over-reported.

Although the findings of this study are interesting—particularly the association between AFE and induction of labor, twin gestation, cesarean delivery, and the combination of older age and ethnic-minority status—they must be interpreted with caution. The study was an elegant mathematical exercise, but I would hesitate to join the authors in sounding too many alarms. For example, without a biological explanation, I would be reluctant to tell clinicians to look for any increased risk of AFE among ethnic minorities.

I would be just as hesitant to “warn” obstetricians about induction of labor. If the risk of AFE attributable to induction is 35%, as the authors maintain, the elimination of induction altogether would only lower the rate of AFE from 2 cases to 1.3 cases for every 100,000 deliveries. Moreover, some of the variables that contribute to the need for induction could also contribute to an increased risk of AFE.

Postpartum cases that occur after cesarean delivery could actually be air embolism misclassified as AFE, especially if the uterus was exteriorized for repair—a phenomenon that has been reported.²

We want to hear from you! Tell us what you think.

From February 2005 to February 2009, Knight and associates identified a total of 60 cases of AFE in the UK Obstetric Surveillance System. Their analysis of these cases, along with the cases of 1,227 women in the control group, is a valuable contribution to our understanding of AFE—an entity that few obstetricians will have the occasion to manage in their professional careers. One of the strengths of the study is the use of a comprehensive database, which made it possible to exclude 26 additional cases originally diagnosed as AFE but determined to be another entity. Scrutiny of these cases suggests that AFE may be over-reported.

Although the findings of this study are interesting—particularly the association between AFE and induction of labor, twin gestation, cesarean delivery, and the combination of older age and ethnic-minority status—they must be interpreted with caution. The study was an elegant mathematical exercise, but I would hesitate to join the authors in sounding too many alarms. For example, without a biological explanation, I would be reluctant to tell clinicians to look for any increased risk of AFE among ethnic minorities.

I would be just as hesitant to “warn” obstetricians about induction of labor. If the risk of AFE attributable to induction is 35%, as the authors maintain, the elimination of induction altogether would only lower the rate of AFE from 2 cases to 1.3 cases for every 100,000 deliveries. Moreover, some of the variables that contribute to the need for induction could also contribute to an increased risk of AFE.

Postpartum cases that occur after cesarean delivery could actually be air embolism misclassified as AFE, especially if the uterus was exteriorized for repair—a phenomenon that has been reported.²

We want to hear from you! Tell us what you think.

From February 2005 to February 2009, Knight and associates identified a total of 60 cases of AFE in the UK Obstetric Surveillance System. Their analysis of these cases, along with the cases of 1,227 women in the control group, is a valuable contribution to our understanding of AFE—an entity that few obstetricians will have the occasion to manage in their professional careers. One of the strengths of the study is the use of a comprehensive database, which made it possible to exclude 26 additional cases originally diagnosed as AFE but determined to be another entity. Scrutiny of these cases suggests that AFE may be over-reported.

Although the findings of this study are interesting—particularly the association between AFE and induction of labor, twin gestation, cesarean delivery, and the combination of older age and ethnic-minority status—they must be interpreted with caution. The study was an elegant mathematical exercise, but I would hesitate to join the authors in sounding too many alarms. For example, without a biological explanation, I would be reluctant to tell clinicians to look for any increased risk of AFE among ethnic minorities.

I would be just as hesitant to “warn” obstetricians about induction of labor. If the risk of AFE attributable to induction is 35%, as the authors maintain, the elimination of induction altogether would only lower the rate of AFE from 2 cases to 1.3 cases for every 100,000 deliveries. Moreover, some of the variables that contribute to the need for induction could also contribute to an increased risk of AFE.

Postpartum cases that occur after cesarean delivery could actually be air embolism misclassified as AFE, especially if the uterus was exteriorized for repair—a phenomenon that has been reported.²

We want to hear from you! Tell us what you think.