Cord entanglement causing premature placental separation and amniotic fluid embolism. Case report.

A woman died undelivered of amniotic fluid embolism. Postmortem examination showed that cord entanglement had caused premature placental separation with a marginal tear of the membranes and so opened a route of entry for amniotic fluid into the subplacental maternal venous sinuses. It is suggested that premature separation of the normally implanted placenta, associated with macro- or microscopic tears of or damage to the fetal membranes, provides a route of entry for amniotic fluid through the placental site in approximately one half of the fatal cases of amniotic fluid embolism.