Atypical twin-to-twin transfusion syndrome: prevalence in a population undergoing fetoscopic laser ablation of communicating placental vessels.

Background: The diagnosis of twin-to-twin transfusion syndrome (TTTS) usually relies the presence of polyhydramnios in one sac with concomitant oligohydramnios in the other sac in a monochorionic diamniotic twin pregnancy. However, TTTS does not always show a linear progression and may present with cardiac compromise or critically abnormal Doppler velocimetry in either fetus before fluid measurements meet the typically used cutoff.

Objective: The aim of this study was to investigate the prevalence of atypical presentations of TTTS in a population undergoing laser fetoscopy.