Oocyte morphology based on first polar body, perivitelline space and cytoplasm correlation with fertilization rate and embryo quality after intracytoplasmic sperm injection.

Objective: To investigate the correlation of oocyte quality based on first polar body, perivitelline space and cytoplasm and fertilization rate, cleavage rate, grade 1-2 embryo rate after intracytoplasmic sperm injection. Methods: Oocyte at metaphase II were evaluated with oocyte morphology based on first polar body, perivitelline space and cytoplasm with light microscope after cumulus removed. Oocyte at metaphase II were graded into five groups. Graded oocytes were compared with each other from fertilization rate, cleavage rate, grade 1-2 embryo rate. Results: The oocytes at grade I had a significant higher fertilization rate, cleavage rate and grade 1-2 embryo rate than oocytes at others grades. (P0.01). The oocytes at grade I had the highest fertilization rate(91.14%), cleavage rate(96.35%)and grade 1-2 embryo rate(83.91%). The fertilization rate, cleavage rate and grade 1-2 embryo rate of oocytes abnormality decreased significantly. The proportion of grade I oocytes, the fertilization rate, the cleavage rate and the grade 1-2 embryo rate were higher when the total number of oocytes retrieved was ≤15 and the oestradiol concentration was 732～1698pmol/l. Conclusions Human oocytes grading based on first polar body, perivitelline space and cytoplasmic morphology correlated with fertilization rate, cleavage rate and grade 1-2 embryo rate.