Effect of Human Follicular Fluid and Synthetic Serum Substitute as a Protein Supplement for In Vitro Fertilization Culture Medium on Human Oocyte Fertilization and Early Embryonic Development

Yang, S H; Kim, Y J; Lee, K S

Abstract

In an effort to improve the in vitro culture conditions of human gametes and embryos in our laboratory, this study was performed to evaluate the efficacy of human follicular fluid and synthetic serum substitute as protein supplement for in vitro fertilization culture medium on human oocyte fertilization and early embryonic development. We retrospectively analyzed IVF cycles performed at Pusan National University Hospital between June 1995 and May 1997. Of these, 142 IVF cycles were reviewed and classified according to the nature of protein supplement used in the embryo culture medium. Three protein supplements utilized during this time period were compared: human follicular fluid (HFF), synthetic serum substitute(SSS; 99193, Irvine Scientific) and fetal cord serum (FCS). Patients in male or ovulatory factor infertility were eliminated. Oocytes were retrieved transvaginally from patients treated with pituitary suppression with GnRH-agonist and ovarian stimulation with follicle stimulating hormone and human menopausal gonadotropin. For insemination and sperm preparation, modified Ham`s F-10 culture medium (9461, Irvine Scientific) was supplemented with either 10% HFF, 10% SSS or 10% FCS. Fertilization was evaluated 18 hours after insemination. For embryo culture, the same culture medium supplemented, with either 20% HFF, 15% SSS or 15% FCS was prepared. Embryo transfer was perfor.med on Day 3 (72 hour postinsemination). Clinical pregnancy was confirmed by the presence of a heartbeat on ultrasound 4~6 weeks after embryo transfer. The results were as follows: 1. Overall oocyte fertilization was lower when SSS was used as an insemination medium supplementation compared to other protein supplements [57.9% SSS (P<0.05) vs 71.7% and 67.0%, respectively, with HFF and FCS]. 2. The proportion of cleaved embryos was higher (91.9%) in the HFF-supplemented culture medium than other protein supplements [88.4% and 82.3%, respectively, with SSS and FCS]. However, these results were not statistically different among the three protein supplements. 3. The proportion of at least 3 mitotic divisions before embryo transfer was not significantly different among the three protein supplements. 4. The incidence of conceptuses without cytoplasmic fragments (grade 1 embryos) was higher in the FCS- upplemented culture medium than other protein supplements [60.6% FCS vs 45.6% HFF (P<0.05) and 51.2% SSS]. 5. There was a higher pregnancy rate with FCS-supplemented culture medium than with other protein supplements [32.8% FCS vs 23.5% SSS (P<0.05) and 30.0% HFF]. The ongoing pregnancy rate, including the babies that were delivered, was not statistically different among three protein supplements. 6. The clinical pregnancy rate was significantly higher for tubal infertility using the FCS supplement (41.0%; P<0.05) and for unexplained infertility with the HFF supplement (40.0%; P<0.05). In conclusion, these results suggest that using HFF as a protein supplement was as useful and as effective as FCS. In addition, the results indicate that SSS was not effective agent in mproving pregnancy rates.