Effects of granulosa cells, cumulus cells, and oocyte density on in vitro fertilization in women.

The objective of this study was to determine if in vitro fertilization (IVF) rate is affected by the diameter of oocyte-cumulus complex (OCC), by coculturing oocytes with autologous granulosa cells, or by increasing the oocyte density in culture medium. Women with previous fertility problems underwent the IVF program. In study 1, the diameter of OCC was graded on retrieval on a scale of 0-3: grade 0 = no cumulus at all; grade 1 = diameter of 75-100 microm; grade 2 = diameter of 125-150 microm; and grade 3 = diameter of 200-225 microm. In study 2, oocytes were cocultured with autologous granulosa cells. In study 3, oocytes were cocultured in groups of one, two, or four. OCCs with a grade > 1.5/3 resulted in a greater (P = 0.04) proportion of embryo/oocyte than did OCCs with a grade < 1.5/3 (0.91 +/- 0.05 vs 0.68 +/- 0.10; mean +/- SEM). Coculturing oocytes with autologous granulosa cells did not affect (P = 0.42) the proportion of embryo/oocyte (0.63 +/- 0.11 vs 0.74 +/- 0.07 in controls). Coculturing oocytes in groups of two or four in culture drop did not affect (P = 0.37 and P = 0.38, respectively) the proportion of embryo/oocyte (0.63 +/- 0.07 vs 0.73 +/- 0.08 in controls, and 0.73 +/- 0.08 vs 0.63 +/- 0.08 in controls, respectively). In conclusion, coculturing oocytes with autologous granulosa cells or increasing the oocyte density from 1 to 2 or 4 oocytes/culture drop, in the context of our study, did not affect rate of IVF and embryo formation. The diameter of OCC at retrieval may give some indication regarding its future fertilization and development. This diameter varies with the type of ovarian stimulation and the patient's age. This variation in diameter does not correlate with oocyte maturity.