Timing of intra‐fetal laser therapy for twin reversed arterial perfusion ( TRAP ) sequence: Retrospective series and systematic review and meta‐analysis

Objective To estimate the neonatal survival rate after intra-fetal laser (IFL) treatment for twin reversed arterial perfusion (TRAP) sequence, and to investigate the effect of gestational age at the time of procedure. Methods Retrospective cohort study of TRAP sequences followed at our institution from 2013-2020. Systematic review and meta-analysis of the neonatal survival rate after IFL was conducted. Both diamniotic and monoamniotic monochorionic pregnancies were included. A subgroup analysis to compare outcomes according to gestational age at procedure (<16(+0) weeks or >= 16(+0) weeks) was planned. Results Thirteen pregnancies were followed at our center and seven were treated with IFL: the survival rate was 57%. Ten studies published between 2008 and 2020 for a total of 156 cases were included in the meta-analysis. The overall neonatal survival after IFL was 79% (95% CI 0.72-0.86, I-2 22%). A random-effects model comparing neonatal survival for IFL performed <16(+0) weeks versus >= 16(+0) weeks showed no significant difference between the two groups (OR = 0.93; 95% CI 0.37-2.33). Conclusion IFL is a safe and minimally invasive technique for the treatment of TRAP sequence, with a survival rate of 79%. Gestational age at treatment (before or after 16 weeks) does not seem to affect neonatal survival rate.