Cycle characteristics and outcome in relation to ovarian response during in vitro fertilization

This retrospective analysis of 148 non-male factor couples sought to determine whether oocyte or embryonic quality was compromised by the magnitude of the ovarian response following clomiphene citrate/human menopausal gonadotropin stimulation for in vitro fertilization.

Increased oocyte numbers were associated with decreased fertilization rates (r = -0.36, P < 0.001) and estradiol/follicle ratios (r = -0.443, P < 0.001), although the quality of the resulting embryos was not affected. Despite reduced fertilization, higher oocyte numbers yielded additional healthy embryos (r = 0.70, P < 0.001) for immediate replacement or cryopreservation. Implantation rates did not differ among groups and no predictive variables were identified.

These results suggest that endometrial receptivity and implantation were not adversely affected by increasing estradiol levels. The decline in oocyte quality associated with the retrieval of larger numbers of oocytes appeared to be offset by the availability of additional embryos for immediate replacement and cryopreservation.