P-501 Live birth rates (LBR) are not influenced by a change in embryo quality imposed by embryo cryopreservation and thawing in single euploid frozen embryo transfers.

Abstract Study question Is a change of embryo quality through vitrification and thawing associated with reduced LBR when single euploid frozen transfer is performed? Summary answer Live birth rates are not influenced by in cryopreservation transfer. What known already Embryo aneuploidy the most significant factor accounts for about 50% implantation failure miscarriage human reproduction. Preimplantation genetic test (PGT-A) presents mean to identify embryos, thereby improving pregnancy reducing early losses. However, after PGT-A on trophectoderm cells at blastocyst stage, embryos have be cryopreserved warmed later procedure. impact ongoing rates, therefore, aim this analysis was evaluate between pre-vitrification post-thaw outcome. design, size, duration This retrospective observational study included total 611 pregnant patients frozen-thawed (FET) tertiary IVF centre April 2017 December 2020. All transferred were biopsy PGT-A, performed either day 5 or 6. Each patient only once into analysis. Endometrial preparation FET natural cycle (NC) as hormonal replacement (HRT). Participants/materials, setting, methods Patients infertility, undergoing ovarian stimulation HRT NC endometrial approach, who achieved pregnancy, included. Embryos morphologically graded based inner cell mass morphology cryopreservation. Four groups initially established (top, good, fair, poor), hence analysis, fair poor qualities combined. Main results role chance A 591 analysed exclusion 20 due occurrence late ectopic pregnancy. Patients’ characteristics follows (mean±SD (min-max)): age 33.87±5.55(20-47) years; AMH 3.20±3.28ng/mL(0.01-35.72); BMI(body index) 26.61±4.86kg/m2(14.84-40.31) AFC 14.00±7.33(1-35). The changes categorized “no change”, “improved” “degraded”. compared top-quality-no group. binary logistic evaluated following regarding their combined LB: top quality-degraded (odds ratio (OR)0.702; 95% confidence interval (CI)0.302-1.635, p = 0.413); good quality-no (OR 1.022; CI:0.457-2.287; 0.958); 0.787; CI:0.330-1.880; P 0.590); quality-improved 0.301; 0.056-1.628; 0.163); fair+poor change(OR 0.521; 0.203-1.340; 0.176); 0.283; 0.056-1.438; 0.128) 1.917; 0.431-8.534; 0.393). No probability LB seen any group its pre-grades. Furthermore, no association found age, BMI, AMH, quality. biopsied 6 instead had decreased 0.516; 0.305-0.875, 0.014). Further on, significantly higher 2.629; 1.606-4.305, <0.001). Limitations, reasons caution Limitation design grading which might subjective bearing interobserver variability. Wider implications findings Whereas does FET, approach increases odds LB. fact should considered personalized treatment choice protocol. Trial registration number applicable