P-140 A prospective randomized study evaluating timelapse culture system versus conventional system for preimplantation embryo development with sibling oocytes

Abstract Study question Prospective clinical study to evaluate the impact of uninterrupted culture, starting from sibling oocytes split to the timelapse and conventional culture systems. Summary answer Uninterrupted culture using timelapse incubation improved preimplantation embryo development to the blastocyst stage, as well as the blastocyst utilization rate. What is known already Modern timelapse embryo culture systems are designed to improve the workflow in IVF labs by automating image capture that allows continuous monitoring of embryos kept under strictly controlled conditions throughout embryo development. However, previous studies comparing the timelapse culture systems and the conventional systems often split patients or treatment cycles rather than sibling gametes, limiting study strength. Study design, size, duration We conducted a prospective randomized clinical study (RCT) between August 2022 and December 2023 with three IVF centres. Sibling oocytes were split randomly in every enrolled cycle, where one half was assigned to the study arm and the other half was assigned to the control arm . The embryos in the study arm were cultured in EmbryoScope+ timelapse system (Vitrolife AB), while those in the control arm were cultured in bench-top conventional incubators. Participants/materials, setting, methods The study enrolled a total of 410 treatment cycles, from which a total of 4,554 M-II oocytes were collected and randomized to the two treatment arms after insemination. We studied the fertilization rate defined by 2PN, as well as blastocyst development rates, morphological grades in Gardner’s criteria and the total embryo utilization rate on day 5-7. The rates per M-II were considered as the primary endpoints and the rates per 2PN as the secondary endpoints. Main results and the role of chance There were statistically significant differences found between the study arm and the control arm in the blastocysts (BL) rate per M-II (41.3% versus 34.7%, p < 0.001), good morphology BL rate per M-II (3BB or better, 26.6% versus 23.0%, p = 0.003), and BL utilization rate per M-II (33.3% versus 29.1%, p = 0.002). 2PN per M-II rate was also slightly higher in the study arm, though the difference was not statistically significant (73.4% versus 71.2%, p = 0.079). The BL development rate, good BL rate and utilized BL rate per 2PN also showed statistically significant differences between these two arms with higher rates in the timelapse arm. Limitations, reasons for caution Although we found statistically significant differences between these two arms, the primary and secondary endpoints of the present study were focused on preimplantation embryo development. The clinical outcomes of transferring those utilized blastocysts remain unassessed. Wider implications of the findings Shown by our prospective RCT of split-sibling analysis, timelapse culture systems offer significant improvements in preimplantation development outcomes and enhance lab workflows, supporting their broader use in clinical embryology. Trial registration number Yes