ABSTRACT
Virtually all monochorionic twin placentas contain vascular connections between the circulatory domains of each twin. In contrast, vascular anastomoses are generally thought not to occur in fused, dichorionic placentation. In the twin-to-twin transfusion syndrome (TTTS) one twin is preferentially perfused by blood from the cotwin via unbalanced placental vascular anastomoses. This vascular shunting results in twins born with discrepant weights, colors and hemoglobins. When one of the TTTS criteria was not present, the pregnancy was defined as "pseudo" TTTS. In pregnancies complicated by "pseudo" TTTS indicate that small twins have abnormal cord insertion more frequently than large twins. We present a case of vascular anastomoses in dichorionic diamniotic-fused placentas resulting in "pseudo" TTTS with a brief review of the literatures concerned.