Spontaneous Twin Anemia Polycythemia Sequence without Amniotic Fluid Discordance Followed by Development of Twin-to-Twin Transfusion Syndrome and Treated by Fetoscopic Laser Photocoagulation.

Twin anemia polycythemia sequence (TAPS) is a form of chronic twin-to-twin blood transfusion that leads to large differences in hemoglobin between twins, yet not necessarily with amniotic fluid discordance, and usually with a few small, unidirectional vascular anastomoses. This report describes a case of spontaneous TAPS that was followed by gradual development of twin-to-twin transfusion syndrome (TTTS) and eventually treated successfully by fetoscopic laser photocoagulation (FLP).