P –215 The degree of perivitelline space (PS) at the pronuclear stage affects subsequent embryonic development in human zygotes

This study included 49 patients who gave written informed consent for our study and were treated with ART in our clinic between March and December 2020. Embryonic development was compared between zygotes with a fully surrounding PS [PS(+)] with those with a partially surrounding PS [PS(-)] at the pronuclear stage. Furthermore, the ZP of PS(-) embryos were artificially removed at the pronuclear stage, and the rate of GQE and BDR were compared with ZP-intact embryos.Participants/materials, setting, methodsThe degree of PS in 128 zygotes was confirmed by hypertonic preparation using 0.125M sucrose-containing HEPES medium. PS(+) and PS(-) embryos were both cultured as ZP-intact, and the rate of GQE was compared. Furthermore, 223 zygotes were divided into three groups: 1) PS(-)/ZP-intact, 2) PS(-)/ZP-free, and 3) PS(+)/ZP-intact, and cultured in an incubator equipped with time-lapse monitoring up to Day 7, and the rate of GQE, BDR and useable embryos were compared between each groups.Main results and the role of chanceThe degree of PS was confirmed by a hypertonic preparation (shrinkage of the ooplasm) in 128 normally-fertilized zygotes obtained from 44 cases. There were 86  PS(-) (67.2%) and 42 PS(+) (32.8%) zygotes. The mean maternal age was 35.9 in PS(-) and 40.5 in PS(+) (P <  0.01), and the rate of GQE was significantly higher in PS(+) [64.3% (27/42)] than in PS(-)[38.4% (33/86)] (P <  0.01). In addition, of 223 normally-fertilized zygotes obtained from 41 c...
Source: Human Reproduction - Category: Reproduction Medicine Source Type: research