Clinical biological features of Ballantyne syndrome and the role of placental hydrops.

Ballantyne syndrome was first described in association with severe hydrops fetalis caused by rhesus isoimmunization, and lately, in association with diverse etiologies of nonimmunological severe fetal hydrops. This report is a case of typical Ballantyne syndrome in association with lethal hydrops fetalis caused by Ebstein's anomaly. It is likely that any severe fetal hydrops with massive placental hydrops may produce Ballantyne syndrome. Hemodilution could be the main biological feature, differentiating Ballantyne syndrome from usual preeclamptic syndromes. Pathophysiological hypotheses are discussed.