Reverse twin-twin transfusion syndrome after fetoscopic laser photocoagulation of chorionic anastomoses: a case report.

A case of severe twin-twin transfusion syndrome (TTTS) which developed at menstrual age of 17 weeks underwent a fetoscopic laser ablation of the anastomosing vessels. The vascular equator of the anastomoses was noticed to be deviated due to marginal cord insertion of the recipient fetus. The procedure was accomplished uneventfully. However, the recipient fetus died 6 h after the procedure. After the pregnancy was terminated, the donor was found to be counterintuitively plethoric, and the recipient was pale. Similar appearances were noted on the placental territories of each fetus. This is consistent with reverse TTTS. Dye injection study and microscopic examination revealed a residual deep vein-vein anastomosis. This subchorionic vascular connection is still a challenge to coagulate with current placental surgery techniques. To the best of our knowledge, this is the first confirmed case of reverse TTTS as a cause of fetal loss following laser photocoagulation. This report also discusses the technical considerations in the complicated case of in utero placental surgery for TTTS.