Timing of delivery following selective laser photocoagulation for twin-to-twin transfusion syndrome

OBJECTIVE: We sought to compare intrauterine risks with postnatal outcome in monochorionic pregnancies operated by fetoscopic laser surgery for twin-to-twin transfusion syndrome. STUDY DESIGN: A cohort of 602 consecutive cases was analyzed. Unexpected prenatal adverse events were identified when a fatal or potentially fatal event occurred that could have been avoided by timely delivery. RESULTS: The prospective risk of an unexpected adverse event dropped from 16.8% (95% confidence interval [CI], 13.6-20.5%) to 0% (95% CI, 0-11%) between 26-36 weeks. At 32 weeks, the residual risk was 1 in 17 (95% CI, 1/28-1/11). The perinatal rate of death or severe brain lesions dropped from 35% (25-47%) in infants delivered at 26-28 weeks down to 3% (1-6%) at 34-36 weeks. CONCLUSION: Our results did not identify an optimal cut-off for elective preterm delivery in laser-operated twin-to-twin transfusion syndrome. Perinatal morbidity appears low from >32 weeks and the decision for elective delivery should be based upon medical history, parental demand, and expert assessment.