A prospective comparison of synthetic serum substitute and human serum albumin in culture for in vitro fertilization-embryo transfer

Objective: To compare the efficacy of a globulin-containing protein source, Synthetic Serum Substitute (Irvine Scientific, Santa Ana, CA) and human serum albumin (HSA) in the early culture of human oocytes and embryos. Design: Oocytes from 31 consecutive IVF cycles were assigned alternately to dishes containing human tubal fluid (HTF) and either Synthetic Serum Substitute or HSA as the protein source. Each semen sample was split for processing in Synthetic Serum Substitute or HSA. Sperm processed in Synthetic Serum Substitute was added to oocytes cultured in Synthetic Serum Substitute, and sperm processed in HSA was added to oocytes cultured in HSA. After determination of fertilization, zygotes were placed in HTF containing the same protein supplement. Before transfer, the embryos were graded morphologically. Main Outcome Measures: Occurrence of normal fertilization and embryo quality as assessed by morphological grading. Results: There was no significant difference in the occurrence of fertilization or in embryo morphological quality between oocytes cultured in Synthetic Serum Substitute as compared with HSA. Conclusions: The use of a globulin-containing protein source in culture for IVF-ET did not improve the fertilization rate or embryo quality. Our design did not allow for demonstration of an effect on pregnancy rate.