Twin-to-twin transfusion syndrome is a severe situation with a risk of pregnancy loss in approximately 80% of cases if no prenatal treatment is performed.

Monochorionic diamniotic pregnancies (one placenta and two amniotic sacs) account for 20% of spontaneous twin pregnancies and almost 5% of medically assisted twin pregnancies; 20% of monochorionic diamniotic pregnancies are complicated by twin-to-twin transfusion syndrome.

Rodrigo Ruano, M.D., Ph.D., explains the five stages of twin-to-twin transfusion syndrome and discusses fetoscopic laser ablation of placental anastomoses, the treatment of choice for stages 2, 3 and 4. By performing this procedure with adequate technique, says Dr. Ruano, specialists are able to increase the chance of delivering two live babies by 70% to 80%.

Dr. Ruano is the division chair of Maternal and Fetal Medicine at Mayo Clinic in Rochester, Minnesota.