Twin-twin transfusion syndrome before and after introduction of laser therapy at the University Hospital Zurich

Introduction: The twin-twin transfusion syndrome (TTTS) is a life threatening disease leading to an abortion or preterm birth in > 80% of untreated monochorionic pregnancies. The aim was to evaluate survival rates of monochorionic twins with TTTS before and after introduction of laser therapy at the University Hospital Zurich and to present the outcome of the children after laser therapy.

Material and methods: Between 2004 – 2011 52 monochorionic twin pregnancies were diagnosed with TTTS. Before introduction of the laser coagulation of placental anastomoses in 2009, 5 out of 19 TTTS patients were treated with laser in other centres and therefore have been excluded. From 2009 – 2011 33 patients with TTTS were identified, but in 11 patients laser treatment could not be performed due to prelabour premature rupture of membranes (PPROM) or too late diagnosis. These patients were excluded as well. Survival rates of one or at least one child and of both children before 2009 and afterwards were evaluated in the 36 included cases. Further outcome parameters of the laser group were: gestational age (GA) at laser therapy and birth, PPROM and intrauterine fetal death (IUFD) rate ≤7 d after operation (OP) and neurological outcome divided into normal or with minor or major abnormalities.

Results: Before introduction of laser therapy the survival rates of one or at least one child and of both children were 21%, 14% and 36%, respectively, compared to 62%, 14% and 76%, respectively, with laser therapy. GA at laser therapy and birth was 20.3 ± 2.4 weeks and 29.6 ± 6.4 weeks; PPROM and IUFD rates ≤7 d after OP were 13% and 7%. Neurological outcome of surviving children after laser therapy was normal in 56%. Minor and major abnormalities were found in 40% and 4%, respectively.

Conclusions: The introduction of the laser therapy for TTTS at USZ let to an increased survival rate of children diagnosed with TTTS during pregnancy. Their neurological outcome is comparable with data of international studies.