Relationship between steroid concentrations in ovarian follicular fluid and oocyte morphology in patients undergoing intracytoplasmic sperm injection (ICSI) treatment

The objective of this study was to investigate the relationship between oocyte morphology and follicular fluid steroid concentrations in patients being treated with intracytoplasmic sperm injection. A total of 82 IVF cycles were evaluated in patients aged 24-40 years. Oocytes at metaphase II were graded into four groups according to the status of the first polar body and the size of the perivitelline space. The proportion of oocytes at the germinal vesicle and germinal vesicle breakdown stages, and the proportion of degenerated oocytes and oocytes with a large polar body were compared with different concentrations of oestradiol, progesterone and testosterone in the follicular fluid. The association between these oocyte characteristics and the ratio of oestradiol:testosterone and oestradiol:progesterone was also analysed. The results showed that oocyte morphology, as assessed by the status of the first polar body and the size of the perivitelline space, is associated with the ratio of oestradiol:testosterone and oestradiol:progesterone but not with the absolute concentrations of oestradiol, progesterone and testosterone in the follicular fluid. A ratio of oestradiol:testosterone > 200 is the best indicator for a small proportion of grade 1 and 2 oocytes (poor quality), a large proportion of grade 3 and 4 oocytes (good quality), and a small proportion of oocytes with cytoplasmic inclusions. These results will be of clinical use in evaluating oocyte quality.