Syndrome with artery-vein anastomoses - donor twin perfuses the recipient twin
Aetiology
- Twin to twin transfusion syndrome is caused by anastomoses of umbilical vessels between the two foetuses in the placenta of monochorionic twins.
Risks
Both foetuses are at risk of developing heart failure and hydrops. The donor suffers high output cardiac failure as a consequence of severe anaemia and the recipient suffers fluid overload.
Management
Pathophysiology
- Both foetuses are at risk of developing heart failure and hydrops
- The donor suffers high output cardiac failure as a consequence of severe anaemia and the recipient suffers fluid overload

Investigations
- USS - oligohydramnios polyhydramnios
Management
- Untreated, TTTS has a high mortality rate for both twins, with the donor more likely to survive
- Treatment is now available at specialist centres:
- Before 26/40 - fetoscopic laser ablation
- >26/40 - amnioreduction/septostomy
- Deliver 34-36/40