P–266 Morphometric assessment of Ratio of inner-cell-mass diameter to blastocyst diameter is an effective criterion to select best embryo for successful outcomes in single blastocyst transfer-cycles

Abstract Study question Can semi-quantitative measurement of ICM diameter vis-à-vis blastocyst diameter, calculated from photographic images, be a significant predictor of implantation potential in single blastocyst transfer cycles? Summary answer A simple, non-invasive measurement of ICM:Blastocyst diameter ratio is a potentially effective predictor of high developmental potential, implantation, live-birth rates in single blastocyst transfer cycles. What is known already: Correlationship between quantitative measurements of blastocyst morphology such as size and shape of ICM and its implantation potential were first reported by Richter et al. Widely used Gardner and Schoolcraft’s qualitative scoring assessment is based on three major variables: expansion stage of blastocyst, cohesiveness of the inner cell mass (ICM), and consistency of trophectodermal (TE) cells. A top quality single blastocyst transfer yields implantation rate nearing 70% and live-birth rate about 50%. If an additional morphological but vital parameter evaluating ICM:Blastocyst diameter ratio is introduced to the Gardner’s blastocyst gradation system, it may help enhance IVF success rates still further. Study design, size, duration A prospective observational cohort study of women (n = 244) undergoing IVF treatment at our private fertility clinic from April 2018 until March 2020. Women with their autologous fertilized oocytes undergoing extended culture and transfer of a single fresh, at least fully expanded (Grade 3) blastocyst with a measurable ICM diameter and blastocyst inner diameter on day 5/6, irrespective of age, cycle number and indication for treatment, were included. Cryopreservation cycles were excluded. Participants/materials, setting, methods Each blastocyst was evaluated for expansion grade, ICM and TE according to Gardner et al. conventional method. Additionally, ratio of ICM diameter w.r.t. blastocyst inner diameter was also calculated from the photographic images on screen using the Hamilton-Thorne software package embedded with their laser system. Measurements were done on blastocysts where expansion had occurred between 114 and 120 hours after insemination. Implantation rates and live-birth rates were the major end-points. Main results and the role of chance A total of 244 blastocyst transfers were performed in same number of women, and 130 clinical pregnancies were achieved (53.3%). The average age of the women was 32.5 ± 4.2 years. The blastocysts that implanted suc