In vitro deleterious effect of hypoxanthine in Ham's Nutrient Mixture F-10 culture medium on human oocyte fertilization and early embryonic development.

OBJECTIVE: To determine whether hypoxanthine in Ham's Nutrient Mixture F-10 (GIBCO, Grand Island, NY) culture medium affects murine embryo development or the outcome of patients undergoing IVF-ET. DESIGN: For the two-cell embryo bioassay, embryos from each female were equally distributed and incubated in Ham's F-10 with or without hypoxanthine supplementation for up to 72 hours. To assess the effect of hypoxanthine in human IVF-ET, oocytes, sperm, and embryos were cultured in Ham's F-10 medium with or without hypoxanthine. Fertilization and embryo cleavage were assessed at 18 and 40 hours, respectively, after insemination. SETTING: University medical research laboratory. PATIENTS, PARTICIPANTS: Nine couples undergoing IVF-ET. RESULTS: Two-cell mouse embryos incubated for 24 hours without hypoxanthine developed 40% to morula, compared with 6.5% for the hypoxanthine group. At 72 hours, 99.5% of the embryos without hypoxanthine reached the expanded blastocyst stage with 65% of them exhibiting hatching, compared with 72% and 19.5%, respectively, for the group with hypoxanthine. Human oocytes cultured in Ham's F-10 without hypoxanthine showed higher fertilization rates than the group incubated in the presence of hypoxanthine (69% versus 53%). The proportion of cleaved embryos was not different between the two culture media; however, the rate of embryos cleaving without cytoplasmic fragments was significantly higher in the group without hypoxanthine (75% versus 35%). CONCLUSION: Ham's F-10 medium containing hypoxanthine significantly reduced embryo development in the two-cell mouse embryo bioassay. Hypoxanthine in culture medium for IVF-ET may have a deleterious effect on human gametes, leading to decreased fertilization and increased incidence of cytoplasmic fragments in the conceptuses.

The use of gonadotropin releasing hormone agonist (GnRHa) in good responders undergoing repeat in vitro fertilization/embryo transfer (IVF/ET).

The use of gonadotropin releasing hormone agonists (Gn-RHa) has been shown to improve the response in patients classified as "poor responders" undergoing ovarian stimulation for in vitro fertilization/embryo transfer (IVF/ET). This study sought to determine whether GnRHa therapy would benefit patients undergoing IVF/ET who had been classified as "good responders" in prior attempts. Twenty-three patients who had completed a prior IVF/ET attempt but who failed to conceive underwent ovarian stimulation using a combination of GnRHa and human menopausal gonadotropin (hMG). Each patient's prior stimulation served as her control and consisted of clomiphene citrate (CC)/hMG in 18 patients and follicle stimulating hormone (FSH) and/or hMG in 5 patients. The numbers of oocytes retrieved, oocytes fertilized, embryos cleaved, and embryos transferred were all significantly greater in cycles treated with GnRHa/hMG compared to control cycles. The clinical pregnancy rate was 39% and the ongoing pregnancy rate was 26% during the cycle when GnRHa pretreatment was utilized. These data suggest that GnRHa therapy is of benefit even to those patients previously classified as "good responders" undergoing ovarian stimulation for IVF/ET.