Relationship between oocyte abnormal morphology and intracytoplasmic sperm injection outcomes: a meta-analysis

The aim of this study was to perform a meta-analysis of the potential effects of oocyte morphological abnormalities on ICSI outcomes. Relevant original papers reporting on the relation between oocyte morphology and ICSI outcomes were identified by searching MEDLINE, EMBASE and the Cochrane Library. The main outcome measures were fertilisation rate and embryo quality. A meta-analysis was performed and Mantel-Haenszel pooled odd ratios (ORs) with 95% confidence intervals (CIs) were calculated to express the relation between the oocyte morphology and the ICSI outcomes. A total of 14 studies reporting 3688 ICSI cycles were included. Our meta-analysis demonstrates that the probability of an oocyte becoming fertilised is significantly reduced by the presence of large IPB (OR: 0.29, CI: 0.09-0.90), large PVS (OR: 0.86, CI: 0.74-0.99), refractile bodies (OR: 0.66, CI: 0.51-0.84) or vacuoles (OR: 0.59, CI: 0.42-0.83). No other investigated morphological abnormalities demonstrated significant relationships with ICSI outcomes. Our data demonstrate that the presence of large IPB, large PVS, refractile bodies or vacuoles is associated with decreased oocyte fertilisation. Our findings might be of importance for selecting embryos for replacement because the effects of oocyte abnormalities on implantation and pregnancy rates remain unclear.