Extreme polycythemia in recipient twin with twin-to-twin transfusion syndrome: a case report

We report a case of severe polycythemia in the recipient twin of a pregnancy with twin-to-twin transfusion syndrome (TTTS). Stage I TTTS was suspected at initial presentation (24 weeks) due to discordant growth associated with a twin oligo-polyhydramnios sequence. Increasing peak systolic velocity (PSV) in the middle cerebral artery (MCA) of the donor twin indicated fetal anemia. In addition, we observed a decreasing MCA-PSV of the recipient twin, indicating polyglobulia. Close follow-up without intervention showed a stable course of TTTS without progression to higher stages.Following caesarean section at 31 2/7 weeks due to preterm premature rupture of membranes of the leading donor twin, the donor twin showed anemia (hematocrit 28%) whereas the recipient twin demonstrated severe polycythemia (hematocrit 88%). Inter-twin difference of reticulocyte counts was high (38% for the donor and 5% for the recipient twin). Transfusion and partial exchange transfusion (PET) were performed in the donor and in the recipient twin, respectively. Normal hematocrit levels were achieved without complication. Perinatal outcome of both twins was good.

Even in a stable course of pregnancy with stage I TTTS, severe polycythemia of the recipient twin can occur and can require careful PET in a specialized center.