Ultrasound-guided fetal blood transfusion for severe rhesus isoimmunization.

Four fetuses with severe rhesus isoimmunization were transfused with packed red blood cells directly into the umbilical vein. The outcome was successful in three. In one infant, this ultrasound-guided technique resulted in resolution of severe fetal hydrops at 27 weeks, allowing delivery of a healthy nonhydropic infant at 33 weeks, and in the other three infants in prolongation of the pregnancy. The last four transfusions were performed after fetal neuromuscular blockade with curare. The procedure would appear to be associated with a low risk of complication and to provide an excellent chance of a successful outcome of a fetus with severe rhesus isoimmunization even when fetal hydrops is present.