Difference in the nucleated red blood cell counts among donor and receipt twins affected by Twin‒Twin transfusion syndrome

A high nucleated red blood cell (NRBC) count at birth is taken as a biomarker of fetal hypoxia. In twin-to-twin transfusion syndrome (TTTS), the communication of placental vessels between the donor and recipient twin creates an imbalance of blood flow resulting in anemia in the donor and polycythemia in the recipient. The anemia in donors results in hypoxia. The NRBC count could be used as a biomarker of chronic hypoxia in donor twins. A literature search shows no previous report on the NRBC count at birth comparing donor and recipient twins in TTTS. We present a case of TTTS with a discussion on the pathophysiology of elevated NRBC at birth in donor twins.