An oocyte score for use in assisted reproduction

PURPOSE: In this work, we describe a system for the morphological scoring of human oocytes prior to fertilisation and use this system to test whether oocyte morphology is an indicator of fertilisation, embryo development and implantation potential. METHODS: The study is a prospective trial of the use of oocyte morphological scores in 822 patients undergoing their first cycle of ICSI. Analyses of oocytes were performed prior to ICSI procedures and the scores compared with fertilisation rates, embryo quality and clinical results. RESULTS: 'Top quality' oocytes had a significantly higher level of fertilisation (96%) as compared to low scoring oocytes (25.6%). Where top quality oocytes formed top quality embryos, we noted a clinical success rate of 63.4%. CONCLUSIONS: Clinical success rates were increased in cases where top quality oocytes formed top quality embryos after ICSI. The analysis of oocyte morphology may represent a positive selection feature during ICSI.