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 (S₂ or G₂) 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. Copyright (C) 1999 American Society for Reproductive Medicine.