Development and integration of an extended embryo culture program

Objective: To study and evaluate a sequential, extended embryo culture system. Design: Prospective study. Setting: University-affiliated IVF clinic. Patient(s): All couples who were treated between October 1997 and July 1998. Intervention(s): A standard human tubal fluid plus 10% serum substitute supplement (SSS) culture medium was used. The embryos were transferred to extended culture medium (S-2 or G(2)) on day 3. Main Outcome Measure(s): Blastocyst formation and implantation and pregnancy rates. Result(s): Forty percent of the 20 donated cryopreserved embryos progressed to the blastocyst stage by day 6. Clinically, 7 (5.6%) of the 125 cycles did not result in a transfer. Blastocyst formation rates ranged from 33%-63% in the five study groups. Implantation rates ranged from 15%-52% and pregnancy rates ranged from 37%-75%. Conclusion(s): Extended culture to day 5 or 6 results in acceptable blastocyst formation rates, implantation rates, and pregnancy rates. (Fertil Steril(R) 1999;72:418-22. (C) 1999 by American Society for Reproductive Medicine.)