[Clinical application for pregnacy outcomes of radiofrequency ablation in complex multiple pregnancies]

Objective: To investigate the safety and effectiveness of radiofrequency ablation (RFA) for selective fetal reduction in complex multiple pregnancies and analyze factors affecting perinatal outcomes. Methods: This was a retrospective case series of 156 patients undergoing selective fetal reduction by RFA in Provincial Hospital Affiliated to Shandong University from July 22th, 2011 to September 12th, 2018. They were divided into five groups according to surgical indications, including 46 cases in the monochorionic twins discordant for fetal anomalies group, 42 cases in the multiple pregnancies for reducing fetal numbers group, 40 cases in the twin to twin transfusion syndrome (TTTS) group, 24 cases in the selective intrauterine growth restriction (sIUGR) group and 4 cases in the twin reversed arterial perfusion sequence (TRAPS) group. According to the gestational age at surgery, patients were divided into two groups: the gestational age at surgery <20 weeks group (75 cases) and the gestational age at surgery≥20 weeks group (81 cases). According to the cycles of RFA required for surgery, patients were divided into two groups: one cycle group (124 cases) and ≥2 cycles group (32 cases). Basic information of patients, surgical process, postoperative complications and pregnancy outcomes were recorded. The growth and development of survival newborns were also followed up. Factors affecting perinatal outcomes were analyzed. Results: (1) The median gestational age at procedure of 156 patients was 20 weeks (14(+5)- 29(+1) weeks). The median cycles of RFA was 1 cycle (1-3 cycles), of which one cycle accounted for 79.5% (124/156). (2) Eleven (7.1%, 11/156) patients experienced intrauterine fetal death, 27 (17.3%, 27/156) patients miscarried, and the overall survival rate was 75.6% (118/156). Premature birth rate before 34 weeks was 19.5% (23/118). There were 129 neonates. The median gestational age at delivery was 37(+3) weeks (28(+2)- 41(+1) weeks) with a mean birth weight of (2 657±700) g. (3) Analysis of pregnancy outcomes based on surgical indications found that, the gestational age at delivery [38 weeks (30(+1)-41(+1) weeks), 36(+4) weeks (29- 39 weeks), 36(+4) weeks (28(+2)-39(+5) weeks), 38 weeks (31-39(+6) weeks), 38(+3) weeks (30(+4)-38(+4) weeks)] and neonatal birth weight [(2 820±671), (2 435±416), (2 497±843), (2 998±718), (2 517±1 087) g] were significantly different among fetal anomalies group, reducing fetal numbers group, TTTS group, sIUGR group and TRAPS group, respectively (all P<0.05). There were no significant differences in the pregnancy outcomes between gestational age at surgery <20 weeks group and gestational age at surgery ≥20 weeks group, or between one cycle group and ≥2 cycles group, respectively (all P>0.05). Conclusions: RFA is a safe and effective procedure in treating complex monochorionic multiple pregnancies. Surgical indications would affect the gestational age at delivery and neonatal outcomes.