P-037 The extent of paternal effect: the blastocyst matters! A retrospective analysis of 1351 single, frozen-thawed embryo-transfers

Abstract Study question Is ongoing pregnancy rate (OPR) impaired by total motile count (TMC) values in IVF/ICSI cycles? Summary answer TMC does not affect the OPR cycles. What is known already Studies exploring paternal role and specifically influence of sperm parameters on outcomes led to contradictory results, especially after blastocysts formation. If a negative impact severe male infertility fertilization rate, embryo morphology blastocyst formation have been described several studies, its effect implantation (IR), live birth (LBR) still debated. In this context, an useful validated tool for evaluation, combining three critical into single indicator quality. design, size, duration Retrospective analysis 1351 freeze-all cycles performed between January 2015 June 2022 Reproductive Sciences Unit Gynaecology/Obstetrics Department San Raffaele Hospital Milan, Italy. Participants/materials, setting, methods We included all first, single, frozen-thawed transfers study period. Transfers obtained frozen semen were excluded. Couples’ characteristics, controlled ovarian stimulation data collected. Semen quality was assessed using grouped quartiles analyses. The primary outcome evaluation potential blastocysts. Main results chance analyzed. Performing logistic regression adjusted confounding factors (maternal age, number oocytes retrieved transferred blastocysts), influenced [odds ratio (OR) = 1.00; confidence interval (CI) 0.99-1.00; p 0.5]. After grouping population TMC, no significant differences found extreme (n 339, ≤4 million n 348, ≥42 respectively), even when confounders [OR 0.99; CI 0.73-1.35; 0.97]. Therefore, blastocysts, once formed, seems be independent from Limitations, reasons caution major limitation retrospective design. Additionally, although positive correlation well described, threshold defining has yet identified. Wider implications findings With larger sample size we confirmed our previous study. Indeed, did demonstrated impair infertile couples submitted IVF/ICSI. Further data, such as obstetrics outcomes, would necessary better define reproduction. Trial registration Not applicable