Endoscopic documentation of unintentional perforation of the dividing membrane during amnioreduction for twin-twin transfusion syndrome

Objective: The purpose of this report is to document endoscopically the occurrence of unintentional piercing of the dividing membrane in a monochorionic twin pregnancy with twin-twin transfusion syndrome (TTTS). Materials and Methods: The dividing membrane was visualized endoscopically during laser therapy in a patient with TTTS who had previously undergone therapeutic amniocentesis. The donor twin had no visible bladder, but the amniotic fluid volume had normalized after amniocentesis. Results: The suspected membrane perforation was identified endoscopically during laser surgery. Five areas of vascular communications were identified and photocoagulated. Conclusions: Sonographic evidence of normalization of the amniotic fluid volumes after therapeutic amniocentesis with persistent nonvisualization of the bladder of the donor twin should not be interpreted as a sign of improvement of TTTS, but rather as indirect evidence of unintentional perforation of the dividing membrane. This complication can be confirmed endoscopically.