Vasa previa.

An active obstetric service can expect to have one perinatal death each year due to vasa previa. Unfortunately, little has been done to improve the diagnosis and treatment of this condition, which presents no risk to the mother but is often fatal to the fetus. The various clinical pictures which can be associated with vasa previa are presented, along with a discussion of the techniques readily available for making the diagnosis: palpation and visualization, amnioscopy, fetal heart monitoring, and various tests for the presence of fetal hemoglobin.