P-479 Prognosis for ongoing pregnancy after recurrent implantation failure (RIF) following IVF/ICSI treatment

Abstract Study question What is the cumulative ongoing pregnancy rate within one year after visiting RIF outpatient clinic in patients with IVF/ICSI treatment? Summary answer The was 42.9% a mean time to of 8.8 months (95% CI 7.5-10.1 months). known already An estimated portion 10-15% IVF experience RIF. Multiple add-on treatments have been proposed, however, evidence for effective clinical therapeutic options still remain scarce. Although it described that might eventually benefit most from ‘keep calm and carry on’ approach, practice often seek clearer answers on their chance request further investigations/interventions. It would be helpful give insight chances achieving RIF, but at this moment little about prognosis. This complicated by lack consistency definition design, size, duration A prospective cohort study 42 one-year follow-up performed, as part MURIM (Multidisciplinary Research Repeated Implantation Failure Recurrent Miscarriages) study. Baseline characteristics including an endometrial assessment ReceptIVFity (vaginal microbiome) test were collected clinic. After minimal participants asked complete questionnaire regarding fertility treatment outcome. Missing information received via medical files. Participants/materials, setting, methods aged 18 38 years old Maastricht University Medical Centre+ between April 2019 until September 2021 included. defined consecutive implantation failure three high quality embryos or ten without criterion. Clinical characteristics, outcome analyzed survival analysis cox hazard regression SPSS version 20.0. p-value < 0.05 considered statistically significant. Main results role Forty-two out 44 contacted responded (response = 95.5%). (Standard Deviation (SD): 0.50%) during first Mean (95%-CI: amount embryo transfers (ETs) 2 (SD: 1.78). per ET (by analysis) first, third sixth 33.1%, 49.3% 63.8%, respectively. To correct possible overestimation normal analysis, rates calculated again using number risk total group (pessimistic rate). pessimistic 48.6%, When comparing baseline univariable women pregnancy, no significant differences found. Nineteen pregnancies reported follow-up, conceived spontaneously (5.3%); four fresh (IVF=15.8% ICSI=5.3%); 14 frozen (IVF=26.4% ICSI=47.4%). resulted livebirths (73.7%); miscarriage stillbirth (15.8%). Limitations, reasons caution prospectively describes prognosis limited short period relatively small sample size. consultation contributed obtained proportionality unclear there control group. Wider implications findings encouraging justifies conservative approach failed ETs. Furthermore, indicates need well-defined, individualized diagnostic criteria define able deviate couples 'bad luck' underlying (treatable) cause. Trial registration NL66835.068.18/METC18-040