The entry of amniotic fluid through a tear in the placental membranes into the maternal circulation. This rare event may occur at any gestational age, but most commonly during labor, delivery or in the immediate postpartum period. The contents of the fluid (e.g., shed fetal cells, meconium, lanugo, vernix) may produce pulmonary or cerebral emboli. Cardiac arrest and disseminated intravascular coagulation (DIC) commonly occur.