Significance of metaphase II human oocyte morphology on ICSI outcome.

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. Retrospective analysis. Medical center. Five hundred sixteen consecutive ICSI cycles. Only couples affected by severe male factor infertility were excluded. 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. Fertilization, pronuclear morphology, embryo quality, pregnancy rate. 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. Morphologic evaluation before ICSI helps to identify MII oocytes with higher developmental potential.