[Invasive therapeutic procedures in monochorionic twins: clinical reality and pending questions]

Monochorionic twin pregnancies (MC) are associated with a higher risk of complications than their bichorionic equivalents. When two fetuses share the same placenta, the two fetal circulations are closely bound by omnipresent vascular anastomoses. The determination of the chorionicity is essential for an adequate management of these particular pregnancies. The twin-to-twin transfusion syndrome (TTTS) is one of the. possible complications and must be considered as an obstetrical emergency. Severe growth restriction of one twin occurs in 11% of MC pregnancies. Before the limit of viability, in some of the cases, selective foeticide using particular methods are mandatory to preserve the wellbeing of the healthy twin. The invasive procedures carried out at the time these complications occur proved their effectiveness, under the condition of being applied by experienced experts. Laser coagulation, TTTS gold standard treatment, is associated with a fetal survival rate equal or higher than 75%. Among MC twins, selective foeticide with bipolar cord coagulation allows an intact survival rate of the other twin in more than 75 to 80% of the cases.