Diffuse brain damage caused by acute twin-twin transfusion during late pregnancy.

Background: Monoamniotic twinning is a relatively rare event with increased antenatal and perinatal mortality. We desscribe a brain damage detected in a surviving monoamniotic twin after intrauterine death of the co-twin at 37 weeks of gestation. Results: Severe entanglement and knotting of the umbilical cords was apparent at the time of delivery and a portion of the cors to the dead twin was narrowed significantly. It was suggested that transfer of blood occurred across placental a lastomoses from the survivor to the dead fetus, resulting in transient but severe hypovolemia in the survivor. It is difficult to prevent this type of brain damage because the course of acute twin-twin transfusion is ven rapid and the damage has already occurred by the time the death of the twin is diagnosed. Conclusions: We suggest that elective delivery should be considered in cases of monoamniotic twin pregnancies with additional risk factors.