Marked Twin-Twin Transfusion in the Absence of Nonimmune Hydrops

The precise pathophysiology of development of nonimmune hydrops in either the recipient or donor twin associated with twin-twin transfusion syndrome is not entirely clear. At times the recipient twin may develop nonimmune hydrops, but at other times the donor twin, and infrequently both, may develop this ominous complication. We present an unusual case of this syndrome in which discordant twins, despite neonatal hematocrit levels of 86 and 21% were both nonhydropic and discuss the possible underlying pathophysiology of this occurrence.