Administration of autologous fetal membranes: Effects on the coagulation in pregnant mini-pigs

Complement C3a expression and tryptase degranulation as promising histopathological tests for diagnosing fatal amniotic fluid embolism

To date, the most recent specific diagnostic investigations for amniotic fluid embolism have been unable to conclusively identify any mechanism of disease other than a physical block to the circulation. We selected eight fatal cases in previously healthy women with uneventful singleton term pregnancies who presented to tertiary care centers in Italy for delivery. Pathologic features were assessed immunohistochemically using anti-fibrinogen, anti-tryptase, anti-C(3a), and anti-cytokeratin antibodies. AE1/AE3 cytokeratin stains proved positive, and tryptase-positive material was documented outside pulmonary mast cells. In all studied cases, expression of complement C(3a) was twofold lower than in the control group, suggesting a possible complement activation in AFE, initiated by fetal antigen leaking into the maternal circulation.

The syndrome of amniotic fluid embolism: a potential contribution of bradykinin

OBJECTIVE

Amniotic fluid embolism is a potentially fatal complication of pregnancy; although several hypotheses have been formulated, the pathophysiology of this condition is not well known. An exaggerated release of bradykinin, which is activated by products of the amniotic fluid that enter the maternal circulation, could explain the symptoms that are present in amniotic fluid embolism. The objective of this study was to assess whether bradykinin is involved in amniotic fluid embolism.

STUDY DESIGN

The plasma bradykinin-generating capacity was measured serially in a patient who experienced amniotic fluid embolism.

RESULTS

The plasma bradykinin-generating capacity was found to be very low at the time of the initial clinical manifestations, which were characterized by severe hypotension, cardiorespiratory arrest, and coagulopathy.

CONCLUSION

This study suggests a potential role for bradykinin release in the pathophysiology of amniotic fluid embolism.