Clinical and biochemical predictors of very preterm birth in twin-to-twin transfusion syndrome treated by fetoscopy

OBJECTIVE: To evaluate pre- and postoperative predictors of preterm birth in twin-to-twin transfusion syndrome treated with fetoscopic placental laser coagulation. STUDY DESIGN: Prospective cohort study (n = 166) assessing cervical length (pre and postoperatively), amniotic fluid interleukin-6, serum C-reactive protein and duration of surgery. Logistic regression was used to investigate associations with preterm delivery. RESULTS: Preterm delivery within 7 days, before 28.0 and 32.0 weeks occurred in 4.8%, 16.8%, and 28.9%, respectively. The only significant predictor of delivery within 7 days was postoperative cervical length (odds ratio [ OR], 0.5; 95% confidence interval [ CI], 0.3-0.9). Concerning delivery before 32.0 weeks, preoperative cervical length (OR, 0.9; 95% CI, 0.8-1.0), and gestational age (OR, 0.8; 95% CI, 0.4-0.9) were independent risk factors but the association was weak. The presence of a single survivor after surgery was associated with a clear reduction of risk (OR, 0.3; 95% CI, 0.1-0.6). Inflammatory biomarkers and duration of surgery did not discriminate risk of prematurity. CONCLUSION: No strong preoperative predictive factor of preterm birth could be identified. A single survivor was a strong protective factor of very preterm birth.