Twin to twin transfusion syndrome (TTTS) is a serious condition that can occur in 10-15% of twins sharing one placenta (i.e. monochorionic)

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.

Donor:

• high output cardiac failure as a consequence of severe anaemia
• Growth retardation
• Oligohydramnios

Recipient:

• suffers fluid overload
• polyhydramnios
• polycythaemia

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 and is by laser transection of the problem vessels in-utero.