Intrauterine death of one twin, with rescue of the other, in twin-twin transfusion syndrome.

Single intrauterine death may occur in twin-twin transfusion syndrome. We investigated why the outcome of the surviving twin is fairly good when the donor twin dies first compared with when the recipient twin dies first. A detailed hemodynamic study was performed using Doppler ultrasound in a twin pregnancy affected by twin-twin transfusion syndrome before and after a single intrauterine death that occurred in the donor twin at 26 weeks' gestation. The recipient twin was expected to die due to severe right cardiac failure with functional stenosis of the pulmonary artery 2 days before the cotwin's death. The donor twin's death caused a prompt resolution of cardiac failure and improvement in other indices, including flow velocity waveform patterns of the umbilical vein, the middle cerebral artery and the ductus venosus. A healthy, premature female neonate weighing 1630 g with a hemoglobin concentration of 17.8 g/dL was delivered by Cesarean section following rupture of the fetal membranes 28 days after the episode. Hemorrhaging from the surviving twin to the dead twin that occurred just before or after the cotwin's death may have contributed to the decrease in volume overload in the recipient twin, leading to a prompt amelioration of the critical hemodynamic indices. The early death of the donor twin may thus have played a significant role in improving the status of the recipient twin in this case of twin-twin transfusion syndrome.