O-181 Utilisation of monopronucleated (1PN) embryos and potential clinical benefits for patients

Abstract Study question Is it beneficial to culture 1PN embryos for clinical use? Summary answer Culturing blastocyst potential use is all patients, especially those with low prognosis. What known already are only a single pronucleus visible at the time of fertilisation check. It generally assumed that such haploid, having 23 chromosomes in each their cells. Given haploid not viable, current guidelines recommend transfering where two pronuclei visualised. Embryo biopsy stage, followed by testing next-generation sequencing (NGS), combined analysis DNA polymorphisms, can reveal whether truly or normal fertilsation has occurred. Previous studies have shown some cases diploid chromosome number may be present. design, size, duration A new policy was put into practice day 5/6. This an ongoing study initiated April 2022. The data reported from eight month period, up until December During this time, we cultured 288 203 patients. Trophectoderm specimens were shipped specialist genetics laboratory they underwent PGT-A using method assesses copy and polymorphisms tandem. Participants/materials, setting, methods If assessed check found discarded, but rather maintained culture. any successfully produced patients received counselling fertility consultant embryologist, giving them options either go ahead transfer (only IVF derived), genetic status clarified PGT-A, freeze without testing, discard embryo. Main results role chance Of (IVF ICSI derived) 85 displayed signs blastulation (29.5%). 134 these derived 20 forming blastocysts (14.9%). 154 65 (42.2%). Three been transferred. Currently one singleton pregnancy, twin pregnancy third resulted live birth. 35 biopsied confirm ploidy status. Six derived, four which diploid. other 29 tested IVF. these, 27 (93.1%) triploid (6.9%). None confirmed as haploid. Traditionally, NGS examine relative number, haploidy/triploidy decreased/increased meaning there no change individual chromosomes. We established embryo advanced PGT method, genotyping thousands scattered across genome, essential accurate diagnosis haploidy/triploidy. Limitations, reasons caution sample size genetically 1PN’s currently too small clearly determine patient. Patients who decided categorised made fully aware risks doing so. Wider implications findings These show clinically large poor prognosis would otherwise had failed cycle. Genetic demonstrates reach stage likely fertilised normally. Trial registration *