Significance of metaphase II human oocyte morphology on ICSI outcome.

OBJECTIVE: To evaluate the influence of specific oocyte morphologic features (morphotypes) on intracytoplasmic sperm injection (ICSI) outcome. The identification of oocyte quality markers is particularly important when a low number of oocytes can be used for IVF.DESIGN: Retrospective analysis.SETTING: Medical center.PATIENT(S): Five hundred sixteen consecutive ICSI cycles. Only couples affected by severe male factor infertility were excluded.INTERVENTION(S): A total of 1,191 metaphase II (MII) oocytes (1-3 per patient) were randomly selected from the cohort of oocytes obtained from each patient and evaluated for morphologic appearance.MAIN OUTCOME MEASURE(S): Fertilization, pronuclear morphology, embryo quality, pregnancy rate.RESULT(S): There was a presence of vacuoles, abnormal I polar body, and large perivitelline space related to a lower fertilization rate. Pronuclear morphology was effected by the presence of a large perivitelline space, diffused cytoplasmic granularity, and/or centrally located granular area. The latter characteristic also negatively related to day 2 embryo quality. According to the odds ratios obtained for each oocyte morphotype to reach at least one outcome, an MII oocyte morphologic score (MOMS) was calculated. A significant relationship was found between MOMS and female age, female basal FSH, and clinical outcome.CONCLUSION(S): Morphologic evaluation before ICSI helps to identify MII oocytes with higher developmental potential.