Consequences of selective fetal growth restriction in perinatal outcomes after fetoscopic laser photocoagulation for twin-to-twin transfusion syndrome, based on single or dual survival

Background Approximately half of twin-to-twin transfusion syndrome (TTTS) cases are complicated by selective fetal growth restriction (sFGR). Although fetoscopic laser photocoagulation (FLP) is the standard treatment, perinatal outcomes in cases with concomitant sFGR-particularly according to single or dual fetal survival after laser-are not well established. Objective To compare post-FLP obstetrical and neonatal outcomes between TTTS+sFGR and isolated TTTS, with separate analyses in pregnancies with immediate single or dual fetal survival. Design This was a retrospective cohort study including all TTTS cases treated with FLP at a single institution between November 2011 and April 2023. TTTS was diagnosed according to Quintero criteria. Outcomes included immediate post-FLP fetal demise (48-hour after FLP), preterm premature rupture of membranes (PPROM), gestational age (GA) at delivery, and neonatal survival, according to post-FLP single or dual fetal survival. Results Among 424 cases, 188 (44.3%) had TTTS+sFGR. Gestational age and cervical length at FLP were similar between groups, but TTTS+sFGR cases showed more severe disease, with a higher proportion of Quintero stage III. Dual fetal survival after FLP was lower in TTTS+sFGR compared with iTTTS (79.6% vs. 88.5%). In pregnancies with single fetal survival post-FLP, TTTS+sFGR was associated with higher rates of delivery before 32 weeks (p=0.03) and increased post-FLP PPROM (p=0.03). Ex-donor fetuses in this group had significantly lower survival at birth and at 30 days compared with iTTTS. In cases with dual survival post-FLP, ex-donor survival at birth and at 30 days remained lower in TTTS+sFGR, while no other perinatal outcomes differed. Conclusion When stratified by immediate single or dual post-FLP survival, pregnancies with TTTS complicated by sFGR showed consistently worse obstetrical and neonatal outcomes compared with isolated TTTS, particularly due to reduced ex donor survival across both groups.