OBJECTIVE: To determine pre-procedure maternal, pregnancy and fetal factors associated with survival until 6 months of age and evaluate temporal trends in survival outcomes over a 25-year period following fetoscopic laser ablation (FLA) of placental anastomoses in monochorionic twin pregnancies with twin-twin transfusion syndrome (TTTS). DESIGN: Retrospective observational study. SETTINGS: A tertiary care fetal centre in Canada. POPULATION OR SAMPLE: One thousand and five patients undergoing TTTS between 1998 and 2023. METHODS: Patient demographics, pregnancy, procedural and outcome details were collected. Predictors for single and dual survival were identified using multivariable logistic regression. Temporal trends in survival outcomes across the study period were also examined. MAIN OUTCOME MEASURES: Fetal/neonatal survival at 6 months and predictors for single and dual survival. RESULTS: Of 915 included fetoscopies, 597 pregnancies (65.2%) achieved dual survival, 217 (23.9%) had a single survivor, and 101 (11%) resulted in dual demise. Survival rates improved significantly over the 25-year study period for both single and dual survival (p = 0.03 and p = 0.0004, respectively). Three significant pre-procedural predictors of dual demise versus one or two survivors were: cervical length ≤ 15 mm (adjusted odds ratio AOR 6.1, 95% CI 2.7-14.1), earlier gestational age (GA) at intervention (AOR 1.2 per earlier week, 95% CI 1.1-1.3), and abnormal donor umbilical artery Doppler flow (AOR 5.1, 95% CI 1.7-15.6). A prediction calculator using this model achieved an area under the curve of 0.65. CONCLUSION: Short cervical length (≤ 15 mm), presence of abnormal donor umbilical artery Doppler waveform, and early GA at time of intervention are significant predictors of fetal/neonatal survival at 6 months following FLA in TTTS and thus, are valuable parameters to consider for pre-procedural counselling.
Ng et al. (2026) studied this question.