P-112 Outcome of laser collapsing blastocyst on clinical pregnancy rate

Abstract Study question To determine clinical pregnancy rate after laser-induced collapse of blastocyst before cryopreservation Summary answer Laser the increases regardless assigned embryo quality group compared to blastocysts vitrified without laser collapsing What is known already Vitrification has been associated with certain risks structure an due intracellular ice crystal formation and impaired shrinkage rate. Blastocyst a large fluid filled cavity requiring additional preparation reduce potential damage. Collapsing shown improve survival following thawing in vitro fertilization (IVF) outcomes including live birth rates design, size, duration . It single-centre retrospective study conducted at private clinic Kazakhstan. We analyzed outcome IVF treatment subsequent frozen transfer 2959 from 1642 women during January 2019-December 2021 Participants/materials, setting, methods The data on technique was collected clinic’s electronic database. were divided into two groups based performed prior vitrification further stratified by excellent, good fair groups. primary Laser-assisted procedure initiated August 2020 clinic. Thus, all previously served as control for Main results role chance 1556 777 1403 865 study. Stratification comparable between more than half embryos defined excellent group, 54% collapsed 52% non-collapsed (p > 0.05). Most under age 35 years old both 1 4 older old, whereas evenly distributed < Clinical highest collapsing, 53% vs 43% respectively 0.001). Overall, showed higher three Despite changes COVID-19 pandemic had not affected but improved use Limitations, reasons caution Retrospective design did provide full baseline information confounders paternal characteristics concurrent conditions. Moreover, period included start which could have Wider implications findings should become routine irrespective woman’s embryo’s Trial registration number applicable