Developmental ability of human oocytes with or without birefringent spindles imaged by Polscope before insemination

BACKGROUND: Birefringent spindles imaged with the Polscope can predict fert ilization rates after intracytoplasmic sperm injection (ICSI), The present study examined the development of human oocytes with or without birefringen t spindles, imaged with the Polscope before ICSI, METHODS: Oocytes were obt ained from stimulated ovaries of consenting patients undergoing oocyte retr ieval for ICSI, Spindles were imaged with the Polscope combined with a comp uterized image analysis system, After imaging and ICSI, oocytes with or wit hout spindles were cultured separately for examination of fertilization and embryo development. A total of 1544 oocytes from 136 cycles were examined with the Polscope and inseminated by ICSI, RESULTS: Spindles were imaged in 82% of oocytes, After ICSI, more oocytes (P < 0.05) with spindles (69.4%) fertilized normally, forming 2 pronuclei, than oocytes without spindles (62 .9%), At day 3, more oocytes (P < 0.01) with spindles (66.3%) developed to 4-11 cell stages than oocytes without spindles (55.4%), Significantly more (P < 0.001) oocytes with spindles developed to morula and blastocyst by day 5 (51.1 versus 30.3%) and day 6 (53.2 versus 29.3%) compared with oocytes without spindles. CONCLUSIONS: The results indicate that the presence of a birefringent spindle in human oocytes can predict not only higher fertiliza tion rate, but also higher embryo developmental competence.