Update on twin-to-twin transfusion syndrome.

Twin-to-twin transfusion syndrome (TTTS) is a serious complication that affects 10-15% of monochorionic multiple pregnancies. Communicating placental vessels on the chorionic plate between the donor and recipient twin are responsible for the imbalance of blood flow. There is evidence for the superiority of fetoscopic laser ablation over serial amnioreductions regarding survival and neurological outcome for stages II-IV TTTS. However, the optimal management of stage I is still debated. The "Solomon" technique showed a significant reduction in recurrent TTTS and post laser twin anemia-polycythemia sequence (TAPS) in comparison to the selective laser method without improvement in perinatal mortality or neonatal morbidity. Survival rates after fetoscopic laser surgery have significantly increased over the last 25 years. High volume centers report up to 70% double survival and at least one survivor in >90%. Long-term neurodevelopmental impairment occurs in about 10% of children after laser surgery. In this review we discuss the optimal management, innovations in laser technique, long-term neurodevelopmental outcome, and future aspects of TTTS treatment.