Reversed twin-to-twin transfusion syndrome following successful laser therapy.

We report a case of severe twin-to-twin transfusion syndrome (TTTS) in which fetoscopic laser ablation was successfully performed at 21 weeks' gestation. Despite successful resolution of signs on ultrasound examination after a period of 7 weeks, the donor developed polyhydramnios whereas the 'initial' recipient maintained normal liquor volume, features suggestive of 'reversed TTTS'. Two live babies were delivered at 31 weeks' gestation with good neonatal outcome. The karyotype of both babies was normal. No significant inter-twin difference in umbilical vein haemoglobin levels was present at delivery and placental injection studies did not identify persistent anastomoses. This case report supports the importance of close monitoring of the pregnancy following apparently successful laser therapy. Further research is needed to understand the pathophysiology of this condition.