23: Gestational and surgical characteristics associated with early preterm birth in twin-twin transfusion syndrome (TTTS) treated by laser surgery


      Preterm birth (PTB) has been shown to be in important risk factor for suboptimal neurodevelopmental outcomes after laser surgery for TTTS. We sought to identify pre-, intra-, and immediate post-operative risk factors for early PTB in laser-treated TTTS patients.

      Study Design

      Laser-treated TTTS patients who delivered after 24.0 gestational weeks were followed prospectively. Univariate and multivariate analyses were performed to identify gestational and surgical characteristics associated with PTB prior to 28.0 and 32.0 weeks of gestation.


      Of 299 eligible patients, the mean (SD) gestational age of delivery was 33.4 (3.5) weeks gestation, with a median of 34.0 (range 24.1-40.1) weeks. 25 (8.4%) delivered prior to 28 weeks and 92 (30.8%) delivered prior to 32 weeks. Multivariable logistic regression analyses demonstrated that earlier gestational age at surgery was associated with PTB before 28 weeks (OR 0.81, 95%CI 0.67-0.99, P = 0.0352), and that the following three factors were associated with an increased risk for PTB before 32 weeks: intra-operative septostomy (OR 5.52, 95%CI 2.33-13.08, P = 0.0001); post-operative membrane detachment (OR 2.37, 95%CI 1.04-5.41, P = 0.0411); and inability to satisfactorily complete the surgical procedure (OR 8.56, 95%CI 1.59-46.17, P = 0.0126). Post-operative cervical length equal to or over 4 cm (OR 0.59, 95%CI 0.34-1.02, P = 0.0572) appeared to have a protective effect. Factors not associated with early PTB included: prior history of PTB, pre-operative cervical length, chorioamnion separation from the internal cervical os (moon sign), and Quintero stage.


      Both gestational and surgical characteristics appeared to contribute to the risk of early PTB in TTTS patients. This information may be useful in counseling patients regarding the risk of early PTB following laser surgery for TTTS.