IMPROVED CLINICAL OUTCOMES FOR IN-VITRO FERTILIZATION WITH DELAY OF EMBRYO-TRANSFER FROM 48 TO 72 HOURS AFTER OOCYTE RETRIEVAL - USE OF GLUCOSE-FREE AND PHOSPHATE-FREE MEDIA

Objective: To evaluate clinical outcomes of day 2 versus day 3 ET usin g a culture media with no glucose or phosphate. Design: Retrospective clinical study. Setting: Hospital-based fertility clinic. Patient(s): One hundred seventy-six NF-ET patients undergoing controlled ovarian s uperovulation. Intervention(s): IVF and delaying the ET by 1 day. Main Outcome Measure(s): Number of blastomeres per embryo, implantation an d pregnancy rates. Result(s): Delaying the ET from day 2 to day 3 afte r oocyte retrieval significantly increased implantation rates (13% ver sus 24%) and ongoing/delivered pregnancy rates per retrieval (26% vers us 44%). Day 3 embryos with greater than or equal to 8 blastomeres res ulted in a significantly higher pregnancy rate (53%) than day 3 embryo s with <8 cells (23%) and day 2 embryos with greater than or equal to 4 cells (31%) or <4 cells (11%). Conclusion(s): Day 3 ET was associate d with a significant increase in implantation and pregnancy rates. Del aying the ET until day 3 may permit the selection of more viable embry os than on day 2. The absence of glucose and phosphate from the cultur e media is compatible with good IVF outcomes. (C) 1998 by American Soc iety for Reproductive Medicine.