North American Fetal Therapy Network: timing of and indications for delivery following laser ablation for twin-twin transfusion syndrome

Background: Despite improvements in fetal survival for pregnancies that are affected by twin-twin transfusion syndrome since the introduction of laser photocoagulation, prematurity remains a major source of neonatal morbidity and death. Objective: To investigate the indications and factors that influence the timing of delivery after laser treatment, we collected delivery information regarding twin-twin transfusion syndrome cases in a large multicenter cohort. Study Design: Eleven North American Fetal Therapy Network centers conducted a retrospective review of twin-twin transfusion syndrome patients who underwent laser photocoagulation. Clinical, demographic, and ultrasound variables that included twin-twin transfusion syndrome stage and gestational age at treatment and delivery were recorded. Primary and secondary maternal and fetal indications for delivery were identified. Univariate analysis was used to select candidate variables with significant correlation with latency and gestational age at delivery. Multivariable Cox regression with competing risk analysis was used to determine the independent associations. Results: A total of 847 pregnancies were analyzed. After laser therapy, the average latency to delivery was 10.11±4.8 weeks, and the mean gestational age at delivery was 30.7±4.5 weeks. Primary maternal indications for delivery comprised 79% of cases. The leading indications included spontaneous labor (46.8%), premature rupture of membranes (17.1%), and placental abruption (8.4%). Primary fetal indications accounted for 21% of cases; the most frequent indications included donor nonreassuring status (20.5%), abnormal donor Doppler evaluations (15.1%), and donor growth restriction (14.5%). The most common secondary indications for delivery were premature rupture of membranes, spontaneous labor, and donor growth restriction. Multivariate modeling found gestational age at diagnosis, stage, history of previous amnioreduction, cerclage, intertwin membrane disruption, procedure complications, and chorioamniotic membrane separation to be predictors for both gestational age at delivery and latency. Conclusion: Premature delivery after laser therapy for twin-twin transfusion syndrome is primarily the result of spontaneous labor, preterm premature rupture of membranes, and nonreassuring status of the donor fetus. Placental abruption was found to be a frequent complication that resulted in early delivery. Future research should be directed toward the goal of prolonging gestation after laser photocoagulation to further reduce morbidity and mortality rates that are associated with twin-twin transfusion syndrome.