[Twin to twin transfusion syndrome].

The incidence of multiple pregnancy has increased by 1.7 times from 1980-1994. Twenty-five percent of all twins are monochorionic diamnionic. The perinatal mortality of monochorionic twins is five times greater than that found in dichorionic twins and the morbidity is eight times greater. The increase in morbidity is due to prematurity, cerebral lesions and congenital malformations. One of the reasons for the increased morbidity is twin-twin transfusion syndrome (TTTS). TTTS occurs in 10-30% of monochorionic twins. TTTS can be treated by either amniocenteses or by lasercoagulation of anastomoses in the placenta. This paper describes the syndrome and reviews the literature. A multination randomized study is necessary to decide which treatment should be preferred.