The maternal hydrops syndrome (Ballantyne syndrome, mirror syndrome, pseudotoxemia, triple edema) is a preeclampsia-like disease observed in some pregnancies with severe fetal and/or placental hydrops. We describe three pregnancies with severe immunological fetal-placental hydrops resulting in fetal death, in spite of intrauterine transfusions. The mothers suffered severe hydrops syndrome, one of which was complicated by an eclamptic convulsion. All three women had anemia, low hematocrit, and elevated plasma uric acid levels. It is suggested that low hematocrit is an important pathophysiological feature in maternal hydrops syndrome.