In the great majority of cases pulmonary embolism is caused by detached venous thrombi and less commonly by emboli of air, oil, or fat. Maternal pulmonary embolism caused by particulate matter contained in amniotic fluid was first described in 1941 by Steiner and Lushbaugh.1 The eight cases reported by them presented a clinical picture of shock coming on during labor or shortly after its conclusion, death occurring within a few minutes or at most within a few hours. The essential pathological condition found on microscopic examination consisted of widespread embolism of small pulmonary arteries, arterioles, and capillaries by the particulate matter found in amniotic fluid and meconium.
Predisposing factors appear to be uterine tetany or exceptionally strong uterine contractions, meconium in the amniotic fluid, intrauterine death of the fetus, an oversized baby, multiparity, and advancing age of the mother. The disease was duplicated clinically and pathologically in rabbits and