OC20.05: A randomised controlled trial in China: microwave ablation versus radiofrequency ablation for fetal reduction in monochorionic twin pregnancies

Using a non-inferiority randomised controlled trial to compare the safety and efficacy of microwave ablation (MWA) and radiofrequency ablation (RFA) in selective reduction of complex monochorionic twin pregnancies. This was a non-inferiority randomised controlled trial conducted from May 2019 to August 2021 at the Third Hospital of Peking University. Twin pregnant women with complex monochorionic requiring selective reduction were recruited, and were randomly allocated in a 1:1 ratio either through MWA or RFA. Senior obstetrician performed all the operations, with the trial protocol having been published (Xie J, et al. BMJ Open 2020). We compared the preterm birth rate, fetal mortality rate, and overall survival rate at 28 days postpartum, and evaluated the neurodevelopment of surviving children at 6 months. The study was approved by the ethical review committee of the Peking University Third Hospital, and was registered at Clinical Trials gov (NCT04014452). In this study, consent was obtained from 144 women, with 72 undergoing RFA and the remaining undergoing MWA. The preoperative characteristics and surgical procedures were comparably similar, with the notable exception of ablation power, which was remarkably higher in the RFA group (35 vs. 30; P = 0.0216). Despite this, the overall survival rates were closely matched (73.61% for RFA vs. 69.44% for MWA; P = 0.5796), with the RFA group reporting 19 deaths and MWA group 22 deaths. Neonatal outcomes showed no significant differences. Following up on 103 surviving children, 31 were lost to follow-up (30.1% loss rate). Nonetheless, 72 survivors yielded valid results, with no significant differences in developmental delay rates nor any brain injury observed in subsequent visits. RFA and MWA for complex monochorionic pregnancies can achieve similar overall survival rate, neonatal outcomes and developmental state, and their results may provide evidence for the extensive use of MWA in intrauterine surgeries.