Objective: To investigate perinatal outcome after endoscopic laser coagulation of the placental vascular anastomoses in severe mid trimester twin-to-twin transfusion syndrome (TTTS).
Study design: In a prospective study between January 1995 and September 1999, we performed laser therapy in 200 consecutive pregnancies with TTTS between 16 and 25 weeks of gestation. We compared outcome of the first group of 73 pregnancies whose outcome has been reported previously in a study comparing laser surgery and serial amniodrainages [Am J Obstet Gynecol 1999;180:717-24], with the following group of 127 patients.
Results: The overall survival rate increased from 61% (89/146) in group 1 to 68% (172/254) in group 2. The percentage of pregnancies with survival of both fetuses was 42% (31/73) in group 1 and increased to 54% (69/127) in group 2 (P=0.142). The survival rate for at least one fetus was 81% (103/127) in group 2. The median gestational age at delivery of liveborn babies was 33.7 weeks in group 1 and 34.4 weeks in group 2 with a median interval of 13 weeks between the intervention and delivery.
Conclusion: This study of a large population of pregnancies with severe second trimester twin-to-twin transfusion syndrome confirms the improvements of outcome after laser therapy as compared to serial amniodrainages reported previously. Furthermore, it shows a trend towards an increase in survival rates with growing experience in this technique, most likely attributable to a more selective identification and efficient coagulation of the placental vascular anastomoses.