EP14.03: Perioperative risk factors of premature delivery immediately after fetoscopic laser photocoagulation for Twin–twin transfusion syndrome

Twin–twin transfusion syndrome (TTTS) is at risk of perinatal mortality and subsequent morbidities in survivors with expectant management. Although fetoscopic laser photocoagulation (FLP) of placental anastomoses for TTTS improves perinatal outcomes in twins, FLP is associated with an increased incidence of premature delivery including preterm delivery (PD) and miscarriage. This study aimed to identify perioperative risk factors for PD in patients who received FLP for TTTS. This was a retrospective cohort study using prospectively recorded perioperative data among patients with monochorionic diamniotic (MCDA) twin gestation who received FLP between 16 and 25 weeks of gestation for TTTS at our centre between January 2011 to June 2021. The exclusion criteria included incomplete surgery due to technical difficulties, reoperation due to recurrent TTTS, and the occurrence of twin anemia-polycythemia sequence (TAPS). The primary outcome was the incidence of PD within 1 week after FLP. Additionally, the hazard ratio (HR) was calculated using the Cox hazard model to determine the relationship between preoperative and intraoperative factors and spontaneous PD within 1 weeks after FLP, censoring for delivery due to maternal and fetal indications. Of 304 patients included, 7 (2.3%) delivered within 1 weeks of FLP. Independent predictors of delivery within 1 weeks of FLP were a history of spontaneous PD (hazard ratio [HR]: 9.99, 95% confidence interval [CI]:1.21–28.82), P = 0.04), vaginal bleeding in the second trimester (HR: 13.57, 95% CI: 2.43–75.80, P < 0.01), and cervical length (CL) after FLP <20mm (HR: 6.13, 95% CI: 1.19-31.67, P = 0.03). The incidence of PD within 1 week after FLP was 2.3%. Patients with a spontaneous history of PD, preoperative vaginal bleeding, and shortened CL just after FLP were more likely to deliver prematurely.