Twin to twin transfusion syndrome (TTTTS) accounts for approximately 10% of monochorionic twin pregnancies and, if left untreated, is associated with high morbidity and mortality rate. A net transfusion of blood flow from one fetus (donor twin) to the other (recipient twin) via placental vascular anastomoses has been supposed as the major etiology of TTTTS. The donor twin becomes hypovolemic and oliguria, oligohydramnios, and a variable degree of growth restriction develop, whereas the recipient twin manifests polyuria, polyhydramnios, and hydrops in response to hypervolemia. TTTTS can be treated by either serial amniocentesis or selective fetoscopic laser coagulation of the communicating vessels. The rationale for removal of large volumes of amniotic fluid is to prevent preterm delivery secondary to polyhydramnios and to improve fetal circulation by reducing pressure on the chorionic plate. On the other hand, the goal of laser therapy is to occlude vascular anastomoses, thereby interrupting intertwin blood exchange. Although laser treatment is associated with increased survival rate and reduced neurologic complications, compared with amnioreduction, it requires highly specialized centers, whereas serial amniocentesis has the advantage of being performed worldwide. Therefore, the optimal treatment for pregnancies complicated with TTTTS is still controversial.

Twin to twin transfusion sindrom (TTTTS) je patološko stanje gde blizanac donor „krvari“ u cirkulaciju fetusa recipijenta preko abnormalnih interblizanačkim placentnih anastomoza. Blizanac donor postaje anemičan, hipovolemičan, zaostaje u rastu i kao posledicu ima smanjenu urinarnu produkciju. Kako funkcija gutanja amnionske tečnosti nije oštećena, volumen plodove vode se progresivno smanjuje. Blizanac recipijent postaje hipervolemičan i policitemičan. Višak cirkulišuće krvi i nemogućnost adekvatne eliminacije nekada može da dovede do pojave hidropsa u težim slučajevima. Povećana urinarna produkcija recipijenta vodi pojavi polihidroamniona i prekomernoj distenziji amnionskog kavuma, kompresije i smanjnje perfuzije donora. Redukcija amnionske tečnosti kod donora rezultuje fiksacijom donora uz zid uterusa (najčešće prednji zid), (Slika 1.) (stanje nazvano stuck twin) 1,36.