Does oocyte granularity affect ICSI prognosis?

ABSTRACT

This study was designed' to evaluate the relationship between oocyte granularity and fertilization rate, further embryonic development and the outcome of ICSI. The study included 986 oocytes retrieved from 92 patients undergoing ICSI treatment that was assessed for oocyte cytoplasm morphology as either normal oocytes with clear cytoplasm and homogeneous fine granularity, granular oocytes that showed dark cytoplasm with granularity either homogeneous affecting the whole cytoplasm [Generalized] or concentrated as a dark mass in the central portion of the oocyte with a clear peripheral ring [Localized] or having cytoplasmic inclusions then, the embryo quality was graded after 16-18, 48 and 60 hours; into grade I [embryos without fragmentation], grade II [embryos with <20% of the volume of the embryo fragmented] and grade III [embryos with enucleate fragments present in 20-50% of the volume of the embryo]. There were 348 [35.3%] oocytes with normal cytoplasm [Group A], 308 [31.2%] oocyte had generalized granularity [Group B], 21 4 [21.7%] with localized dense central granularity, [Group C] and 116 [11.8%] with cytoplasmic inclusions [Group D]. Fertilization rate, determined after 16-1 8 hours, was 69% [n=240] in group A, 64% [n=197] in group B, 60% [n=128] in group C and 65 [56%] in group D. Cleavage rate determined at 48 hours after ICSI was 60%, 52%, 43% and 32% in the four groups, respectively. Cytoplasmic fragmentation, evaluated 60 hours after ICSI, was reported in 0-10% of group -4, 10-20% of group B, 15-25% in-group C and >25% in group D. Good quality embryo was detected in 40% in-group A oocytes, 25% in group 8, 10% in group C and <10% in group D oocytes. There was a significant difference in cleavage rate of fertilized oocytes categorized according to cytoplasmic granularity, [F=4.34, p=0.0375] with a significant increase of percentage of cytoplasmic fragmentation in oocytes with dense granularity, compared to oocytes with $ne granularity, [F=100.96, p=0.0000] and a significant difference in percentage of good quality embryos between fertilized oocytes categorized according to cytoplasmic granularity, [F=7.469, p=0.0275]. It could be concluded that although oocyte granularity does not significantly affect fertilize ability in ICSI procedure; it affects embryo cleavage rate and embryo fragmentation significantly and hence the predictability of the outcome of ICSI procedure reflected as the percentage of good quality embryo