Fetomaternal bleeding as a cause for "unexplained" fetal death.

Among a series of 29 antepartum fetal deaths without apparent cause, 4 (13.8%) were apparently due to transplacental fetal exsanguination. This represents 3.4% of all fetal deaths and 0.04% of all births in a series of 9223 deliveries. The principal conclusion of this study is that massive fetal maternal hemorrhage occurring without apparent cause or predisposing factors represents a significant cause of fetal wastage, examination of which should be included in evaluation of these patients.